diff --git a/generators/php/codegen/src/AsIs.ts b/generators/php/codegen/src/AsIs.ts
index 648935c3bdb..bb332e401a2 100644
--- a/generators/php/codegen/src/AsIs.ts
+++ b/generators/php/codegen/src/AsIs.ts
@@ -25,6 +25,7 @@ export enum AsIsFiles {
     DateArrayTypeTest = "Json/DateArrayTypeTest.Template.php",
     EmptyArraysTest = "Json/EmptyArraysTest.Template.php",
     EnumTest = "Json/EnumTest.Template.php",
+    TraitTest = "Json/TraitTest.Template.php",
     InvalidTypesTest = "Json/InvalidTypesTest.Template.php",
     MixedDateArrayTypeTest = "Json/MixedDateArrayTypeTest.Template.php",
     NestedUnionArrayTypeTest = "Json/NestedUnionArrayTypeTest.Template.php",
diff --git a/generators/php/codegen/src/asIs/Json/TraitTest.Template.php b/generators/php/codegen/src/asIs/Json/TraitTest.Template.php
new file mode 100644
index 00000000000..26178b5ea81
--- /dev/null
+++ b/generators/php/codegen/src/asIs/Json/TraitTest.Template.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace <%= namespace%>;
+
+use <%= coreNamespace%>\Json\SerializableType;
+use <%= coreNamespace%>\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
\ No newline at end of file
diff --git a/generators/php/codegen/src/ast/Class.ts b/generators/php/codegen/src/ast/Class.ts
index abe94e66edf..7b26e5a8813 100644
--- a/generators/php/codegen/src/ast/Class.ts
+++ b/generators/php/codegen/src/ast/Class.ts
@@ -7,6 +7,8 @@ import { Field } from "./Field";
 import { Method } from "./Method";
 import { Comment } from "./Comment";
 import { orderByAccess } from "./utils/orderByAccess";
+import { ClassReference } from "./ClassReference";
+import { Trait } from "./Trait";
 
 export declare namespace Class {
     interface Args {
@@ -20,6 +22,8 @@ export declare namespace Class {
         docs?: string;
         /* The class to inherit from if any */
         parentClassReference?: AstNode;
+        /* The traits that this class uses, if any */
+        traits?: ClassReference[];
     }
 
     interface Constructor {
@@ -38,18 +42,20 @@ export class Class extends AstNode {
     public readonly abstract: boolean;
     public readonly docs: string | undefined;
     public readonly parentClassReference: AstNode | undefined;
+    public readonly traits: ClassReference[];
 
     public readonly fields: Field[] = [];
     public readonly methods: Method[] = [];
     private constructor_: Class.Constructor | undefined;
 
-    constructor({ name, namespace, abstract, docs, parentClassReference }: Class.Args) {
+    constructor({ name, namespace, abstract, docs, parentClassReference, traits }: Class.Args) {
         super();
         this.name = name;
         this.namespace = namespace;
         this.abstract = abstract ?? false;
         this.docs = docs;
         this.parentClassReference = parentClassReference;
+        this.traits = traits ?? [];
     }
 
     public addConstructor(constructor: Class.Constructor): void {
@@ -64,6 +70,10 @@ export class Class extends AstNode {
         this.methods.push(method);
     }
 
+    public addTrait(traitClassReference: ClassReference): void {
+        this.traits.push(traitClassReference);
+    }
+
     public write(writer: Writer): void {
         if (this.abstract) {
             writer.write("abstract ");
@@ -77,6 +87,17 @@ export class Class extends AstNode {
         writer.newLine();
         writer.writeLine("{");
         writer.indent();
+        if (this.traits.length > 0) {
+            writer.write("use ");
+            this.traits.forEach((trait, index) => {
+                if (index > 0) {
+                    writer.write(",");
+                }
+                writer.writeNode(trait);
+            });
+            writer.writeTextStatement("");
+            writer.newLine();
+        }
 
         this.writeFields({ writer, fields: orderByAccess(this.fields) });
         if (this.constructor != null || this.methods.length > 0) {
@@ -141,13 +162,15 @@ export class Class extends AstNode {
     }
 
     private writeFields({ writer, fields }: { writer: Writer; fields: Field[] }): void {
-        fields.forEach((field, index) => {
-            if (index > 0) {
-                writer.newLine();
-            }
-            field.write(writer);
-            writer.writeNewLineIfLastLineNot();
-        });
+        fields
+            .filter((field) => !field.inherited)
+            .forEach((field, index) => {
+                if (index > 0) {
+                    writer.newLine();
+                }
+                field.write(writer);
+                writer.writeNewLineIfLastLineNot();
+            });
     }
 
     private writeMethods({ writer, methods }: { writer: Writer; methods: Method[] }): void {
diff --git a/generators/php/codegen/src/ast/DataClass.ts b/generators/php/codegen/src/ast/DataClass.ts
index f3c5e3efa9a..f2e4b3a6f8c 100644
--- a/generators/php/codegen/src/ast/DataClass.ts
+++ b/generators/php/codegen/src/ast/DataClass.ts
@@ -9,6 +9,8 @@ import { Type } from "./Type";
 import { orderByAccess } from "./utils/orderByAccess";
 import { php } from "..";
 import { convertFromPhpVariableName } from "./utils/convertFromPhpVariableName";
+import { Trait } from "./Trait";
+import { ClassReference } from "../php";
 
 const CONSTRUCTOR_PARAMETER_NAME = "values";
 
@@ -21,11 +23,11 @@ export class DataClass extends AstNode {
     public readonly namespace: string;
     private class_: Class;
 
-    constructor({ name, namespace, abstract, docs, parentClassReference }: DataClass.Args) {
+    constructor({ name, namespace, abstract, docs, parentClassReference, traits }: DataClass.Args) {
         super();
         this.name = name;
         this.namespace = namespace;
-        this.class_ = new Class({ name, namespace, abstract, docs, parentClassReference });
+        this.class_ = new Class({ name, namespace, abstract, docs, parentClassReference, traits });
     }
 
     public addField(field: Field): void {
@@ -35,6 +37,9 @@ export class DataClass extends AstNode {
     public addMethod(method: Method): void {
         this.class_.addMethod(method);
     }
+    public addTrait(traitClassRefeference: ClassReference): void {
+        this.class_.addTrait(traitClassRefeference);
+    }
 
     public write(writer: Writer): void {
         const orderedFields = orderByAccess(this.class_.fields).map(
diff --git a/generators/php/codegen/src/ast/Field.ts b/generators/php/codegen/src/ast/Field.ts
index 8675cb4a10c..fd836a7f359 100644
--- a/generators/php/codegen/src/ast/Field.ts
+++ b/generators/php/codegen/src/ast/Field.ts
@@ -25,6 +25,8 @@ export declare namespace Field {
         inlineDocs?: string;
         /* Field attributes */
         attributes?: Attribute[];
+        /* Indicates that this field is inherited and should not be written to the class. */
+        inherited?: boolean;
     }
 }
 
@@ -37,8 +39,9 @@ export class Field extends AstNode {
     private docs: string | undefined;
     private inlineDocs: string | undefined;
     private attributes: Attribute[];
+    public readonly inherited: boolean;
 
-    constructor({ name, type, access, readonly_, initializer, docs, inlineDocs, attributes }: Field.Args) {
+    constructor({ name, type, access, readonly_, initializer, docs, inlineDocs, attributes, inherited }: Field.Args) {
         super();
         this.name = convertToPhpVariableName(name);
         this.type = type;
@@ -48,6 +51,7 @@ export class Field extends AstNode {
         this.docs = docs;
         this.inlineDocs = inlineDocs;
         this.attributes = attributes ?? [];
+        this.inherited = inherited ?? false;
     }
 
     public write(writer: Writer): void {
diff --git a/generators/php/codegen/src/ast/Trait.ts b/generators/php/codegen/src/ast/Trait.ts
new file mode 100644
index 00000000000..a3a10a2264b
--- /dev/null
+++ b/generators/php/codegen/src/ast/Trait.ts
@@ -0,0 +1,101 @@
+import { AstNode } from "./core/AstNode";
+import { Writer } from "./core/Writer";
+import { Field } from "./Field";
+import { Method } from "./Method";
+import { Comment } from "./Comment";
+import { orderByAccess } from "./utils/orderByAccess";
+import { ClassReference } from "./ClassReference";
+
+export declare namespace Trait {
+    interface Args {
+        /* The name of the PHP trait */
+        name: string;
+        /* The namespace of the PHP trait */
+        namespace: string;
+        /* Docs associated with the trait */
+        docs?: string;
+        /* The traits that this trait uses, if any */
+        traits?: ClassReference[];
+    }
+}
+
+export class Trait extends AstNode {
+    public readonly name: string;
+    public readonly namespace: string;
+    public readonly docs: string | undefined;
+    public readonly traits: ClassReference[];
+
+    public readonly fields: Field[] = [];
+    public readonly methods: Method[] = [];
+
+    constructor({ name, namespace, docs, traits }: Trait.Args) {
+        super();
+        this.name = name;
+        this.namespace = namespace;
+        this.docs = docs;
+        this.traits = traits ?? [];
+    }
+
+    public addField(field: Field): void {
+        this.fields.push(field);
+    }
+
+    public addMethod(method: Method): void {
+        this.methods.push(method);
+    }
+
+    public write(writer: Writer): void {
+        this.writeComment(writer);
+        writer.write(`trait ${this.name} `);
+        writer.newLine();
+        writer.writeLine("{");
+        writer.indent();
+
+        if (this.traits.length > 0) {
+            writer.write("use ");
+            this.traits.forEach((trait, index) => {
+                if (index > 0) {
+                    writer.write(",");
+                }
+                writer.writeNode(trait);
+            });
+            writer.writeTextStatement("");
+            writer.newLine();
+        }
+
+        this.writeFields({ writer, fields: orderByAccess(this.fields) });
+        this.writeMethods({ writer, methods: orderByAccess(this.methods) });
+
+        writer.dedent();
+        writer.writeLine("}");
+        return;
+    }
+
+    private writeComment(writer: Writer): void {
+        if (this.docs == null) {
+            return undefined;
+        }
+        const comment = new Comment({ docs: this.docs });
+        comment.write(writer);
+    }
+
+    private writeFields({ writer, fields }: { writer: Writer; fields: Field[] }): void {
+        fields.forEach((field, index) => {
+            if (index > 0) {
+                writer.newLine();
+            }
+            field.write(writer);
+            writer.writeNewLineIfLastLineNot();
+        });
+    }
+
+    private writeMethods({ writer, methods }: { writer: Writer; methods: Method[] }): void {
+        methods.forEach((method, index) => {
+            if (index > 0) {
+                writer.newLine();
+            }
+            method.write(writer);
+            writer.writeNewLineIfLastLineNot();
+        });
+    }
+}
diff --git a/generators/php/codegen/src/ast/index.ts b/generators/php/codegen/src/ast/index.ts
index f681bee66e4..eeec5368649 100644
--- a/generators/php/codegen/src/ast/index.ts
+++ b/generators/php/codegen/src/ast/index.ts
@@ -1,6 +1,7 @@
 export { Array_ as Array } from "./Array";
 export { Attribute } from "./Attribute";
 export { Class } from "./Class";
+export { Trait } from "./Trait";
 export { ClassInstantiation } from "./ClassInstantiation";
 export { ClassReference } from "./ClassReference";
 export { CodeBlock } from "./CodeBlock";
diff --git a/generators/php/codegen/src/constants.ts b/generators/php/codegen/src/constants.ts
new file mode 100644
index 00000000000..80d5bc5b5a8
--- /dev/null
+++ b/generators/php/codegen/src/constants.ts
@@ -0,0 +1 @@
+export const TRAITS_DIRECTORY = "Traits";
diff --git a/generators/php/codegen/src/context/AbstractPhpGeneratorContext.ts b/generators/php/codegen/src/context/AbstractPhpGeneratorContext.ts
index 12460deb336..a707a65234b 100644
--- a/generators/php/codegen/src/context/AbstractPhpGeneratorContext.ts
+++ b/generators/php/codegen/src/context/AbstractPhpGeneratorContext.ts
@@ -9,7 +9,8 @@ import {
     Subpackage,
     SubpackageId,
     FernFilepath,
-    PrimitiveTypeV1
+    PrimitiveTypeV1,
+    ObjectTypeDeclaration
 } from "@fern-fern/ir-sdk/api";
 import { BasePhpCustomConfigSchema } from "../custom-config/BasePhpCustomConfigSchema";
 import { PhpProject } from "../project";
@@ -20,6 +21,7 @@ import { AsIsFiles } from "../AsIs";
 import { RelativeFilePath } from "@fern-api/fs-utils";
 import { php } from "..";
 import { GLOBAL_NAMESPACE } from "../ast/core/Constant";
+import { TRAITS_DIRECTORY } from "../constants";
 
 export interface FileLocation {
     namespace: string;
@@ -283,6 +285,35 @@ export abstract class AbstractPhpGeneratorContext<
         }
     }
 
+    public getUnderlyingObjectTypeDeclaration(typeReference: TypeReference): ObjectTypeDeclaration {
+        switch (typeReference.type) {
+            case "named": {
+                const declaration = this.getTypeDeclarationOrThrow(typeReference.typeId);
+                if (declaration.shape.type === "alias") {
+                    return this.getUnderlyingObjectTypeDeclaration(declaration.shape.aliasOf);
+                }
+                if (declaration.shape.type === "object") {
+                    return declaration.shape;
+                }
+                throw new Error("Type is not an object type");
+            }
+            case "primitive":
+            case "unknown":
+            case "container":
+        }
+        throw new Error("Type is not an object type");
+    }
+
+    public getUnderlyingObjectTypeDeclarationOrThrow(typeDeclaration: TypeDeclaration): ObjectTypeDeclaration {
+        if (typeDeclaration.shape.type === "alias") {
+            return this.getUnderlyingObjectTypeDeclaration(typeDeclaration.shape.aliasOf);
+        }
+        if (typeDeclaration.shape.type === "object") {
+            return typeDeclaration.shape;
+        }
+        throw new Error("Type is not an object type");
+    }
+
     public maybeLiteral(typeReference: TypeReference): Literal | undefined {
         if (typeReference.type === "container" && typeReference.container.type === "literal") {
             return typeReference.container.literal;
@@ -327,6 +358,7 @@ export abstract class AbstractPhpGeneratorContext<
             AsIsFiles.DateArrayTypeTest,
             AsIsFiles.EmptyArraysTest,
             AsIsFiles.InvalidTypesTest,
+            AsIsFiles.TraitTest,
             AsIsFiles.MixedDateArrayTypeTest,
             AsIsFiles.NestedUnionArrayTypeTest,
             AsIsFiles.NullableArrayTypeTest,
@@ -341,6 +373,11 @@ export abstract class AbstractPhpGeneratorContext<
 
     public abstract getLocationForTypeId(typeId: TypeId): FileLocation;
 
+    public getTraitLocationForTypeId(typeId: TypeId): FileLocation {
+        const typeDeclaration = this.getTypeDeclarationOrThrow(typeId);
+        return this.getFileLocation(typeDeclaration.name.fernFilepath, TRAITS_DIRECTORY);
+    }
+
     protected getFileLocation(filepath: FernFilepath, suffix?: string): FileLocation {
         let parts = filepath.allParts.map((path) => path.pascalCase.safeName);
         parts = suffix != null ? [...parts, suffix] : parts;
diff --git a/generators/php/codegen/src/context/PhpTypeMapper.ts b/generators/php/codegen/src/context/PhpTypeMapper.ts
index 305d5836886..ba5d9b4780e 100644
--- a/generators/php/codegen/src/context/PhpTypeMapper.ts
+++ b/generators/php/codegen/src/context/PhpTypeMapper.ts
@@ -58,6 +58,13 @@ export class PhpTypeMapper {
         });
     }
 
+    public convertToTraitClassReference(declaredTypeName: { typeId: TypeId; name: Name }): ClassReference {
+        return new php.ClassReference({
+            name: this.context.getClassName(declaredTypeName.name),
+            namespace: this.context.getTraitLocationForTypeId(declaredTypeName.typeId).namespace
+        });
+    }
+
     private convertContainer({ container, preserveEnums }: { container: ContainerType; preserveEnums: boolean }): Type {
         switch (container.type) {
             case "list":
diff --git a/generators/php/codegen/src/php.ts b/generators/php/codegen/src/php.ts
index f96f5f538df..3536da4f6f8 100644
--- a/generators/php/codegen/src/php.ts
+++ b/generators/php/codegen/src/php.ts
@@ -3,6 +3,7 @@ import {
     Array as Array_,
     Attribute,
     Class,
+    Trait,
     ClassInstantiation,
     ClassReference,
     CodeBlock,
@@ -27,6 +28,10 @@ export function class_(args: Class.Args): Class {
     return new Class(args);
 }
 
+export function trait(args: Trait.Args): Trait {
+    return new Trait(args);
+}
+
 export function classReference(args: ClassReference.Args): ClassReference {
     return new ClassReference(args);
 }
@@ -76,6 +81,7 @@ export {
     Array,
     Attribute,
     Class,
+    Trait,
     ClassInstantiation,
     ClassReference,
     CodeBlock,
diff --git a/generators/php/codegen/src/project/PhpFile.ts b/generators/php/codegen/src/project/PhpFile.ts
index 7603120518a..bd584e4d1f2 100644
--- a/generators/php/codegen/src/project/PhpFile.ts
+++ b/generators/php/codegen/src/project/PhpFile.ts
@@ -4,7 +4,7 @@ import path from "path";
 import { BasePhpCustomConfigSchema } from "../custom-config/BasePhpCustomConfigSchema";
 import { File } from "@fern-api/generator-commons";
 import { Class } from "../ast/Class";
-import { Enum } from "../ast";
+import { Enum, Trait } from "../ast";
 import { DataClass } from "../ast/DataClass";
 
 export type Namespace = string;
@@ -12,7 +12,7 @@ export type Namespace = string;
 export declare namespace PhpFile {
     interface Args {
         /* The class to be written to the PHP File */
-        clazz: Class | DataClass | Enum;
+        clazz: Class | DataClass | Trait | Enum;
         /* Directory of the filepath */
         directory: RelativeFilePath;
         /* The root namespace of the project. Can be pulled directly from context. */
@@ -49,7 +49,7 @@ function phpFileContent({
     rootNamespace,
     customConfig
 }: {
-    clazz: Class | DataClass | Enum;
+    clazz: Class | DataClass | Trait | Enum;
     rootNamespace: string;
     customConfig: BasePhpCustomConfigSchema;
 }): string {
diff --git a/generators/php/model/src/ModelGeneratorCli.ts b/generators/php/model/src/ModelGeneratorCli.ts
index ccf11dfd6fd..1307d0bca5b 100644
--- a/generators/php/model/src/ModelGeneratorCli.ts
+++ b/generators/php/model/src/ModelGeneratorCli.ts
@@ -4,6 +4,7 @@ import { IntermediateRepresentation } from "@fern-fern/ir-sdk/api";
 import { ModelCustomConfigSchema } from "./ModelCustomConfig";
 import { ModelGeneratorContext } from "./ModelGeneratorContext";
 import { generateModels } from "./generateModels";
+import { generateTraits } from "./generateTraits";
 
 export class ModelGeneratorCLI extends AbstractPhpGeneratorCli<ModelCustomConfigSchema, ModelGeneratorContext> {
     protected constructContext({
@@ -38,6 +39,7 @@ export class ModelGeneratorCLI extends AbstractPhpGeneratorCli<ModelCustomConfig
 
     protected async generate(context: ModelGeneratorContext): Promise<void> {
         generateModels(context);
+        generateTraits(context);
         await context.project.persist();
     }
 }
diff --git a/generators/php/model/src/generateTraits.ts b/generators/php/model/src/generateTraits.ts
new file mode 100644
index 00000000000..a06f26bfc68
--- /dev/null
+++ b/generators/php/model/src/generateTraits.ts
@@ -0,0 +1,28 @@
+import { ModelGeneratorContext } from "./ModelGeneratorContext";
+import { TraitGenerator } from "./trait/TraitGenerator";
+
+export function generateTraits(context: ModelGeneratorContext): void {
+    const extendedTypeIdsFromTypes = Object.values(context.ir.types).flatMap((typeDeclaration) =>
+        typeDeclaration.shape._visit<string[]>({
+            alias: () => [],
+            enum: () => [],
+            object: (objectDeclaration) => objectDeclaration.extends.map((declaredTypeName) => declaredTypeName.typeId),
+            undiscriminatedUnion: () => [],
+            union: () => [],
+            _other: () => []
+        })
+    );
+    const extendedTypeIdsFromInlinedRequests = Object.values(context.ir.services)
+        .flatMap((service) => service.endpoints)
+        .flatMap((endpoint) => {
+            return endpoint.requestBody?.type === "inlinedRequestBody"
+                ? endpoint.requestBody.extends.map((declaredTypeName) => declaredTypeName.typeId)
+                : [];
+        });
+    for (const typeId of new Set([...extendedTypeIdsFromTypes, ...extendedTypeIdsFromInlinedRequests])) {
+        const typeDeclaration = context.getTypeDeclarationOrThrow(typeId);
+        const objectTypeDeclaration = context.getUnderlyingObjectTypeDeclarationOrThrow(typeDeclaration);
+        const file = new TraitGenerator(context, typeDeclaration, objectTypeDeclaration).generate();
+        context.project.addSourceFiles(file);
+    }
+}
diff --git a/generators/php/model/src/index.ts b/generators/php/model/src/index.ts
index 14e382f1a72..f7ba0831e8d 100644
--- a/generators/php/model/src/index.ts
+++ b/generators/php/model/src/index.ts
@@ -1,2 +1,3 @@
 export * from "./ModelGeneratorCli";
 export { generateModels } from "./generateModels";
+export { generateTraits } from "./generateTraits";
diff --git a/generators/php/model/src/object/ObjectGenerator.ts b/generators/php/model/src/object/ObjectGenerator.ts
index 3437940bc93..719b6257f8a 100644
--- a/generators/php/model/src/object/ObjectGenerator.ts
+++ b/generators/php/model/src/object/ObjectGenerator.ts
@@ -2,7 +2,7 @@ import { join, RelativeFilePath } from "@fern-api/fs-utils";
 import { PhpFile } from "@fern-api/php-codegen";
 import { FileGenerator } from "@fern-api/php-codegen";
 import { php } from "@fern-api/php-codegen";
-import { ObjectTypeDeclaration, TypeDeclaration } from "@fern-fern/ir-sdk/api";
+import { ObjectProperty, ObjectTypeDeclaration, TypeDeclaration } from "@fern-fern/ir-sdk/api";
 import { ModelCustomConfigSchema } from "../ModelCustomConfig";
 import { ModelGeneratorContext } from "../ModelGeneratorContext";
 
@@ -23,24 +23,17 @@ export class ObjectGenerator extends FileGenerator<PhpFile, ModelCustomConfigSch
         const clazz = php.dataClass({
             ...this.classReference,
             docs: this.typeDeclaration.docs,
-            parentClassReference: this.context.getSerializableTypeClassReference()
+            parentClassReference: this.context.getSerializableTypeClassReference(),
+            traits: this.objectDeclaration.extends.map((declaredTypeName) =>
+                this.context.phpTypeMapper.convertToTraitClassReference(declaredTypeName)
+            )
         });
 
-        // TODO: handle extended properties
         for (const property of this.objectDeclaration.properties) {
-            const convertedType = this.context.phpTypeMapper.convert({ reference: property.valueType });
-            clazz.addField(
-                php.field({
-                    type: convertedType,
-                    name: this.context.getPropertyName(property.name.name),
-                    access: "public",
-                    docs: property.docs,
-                    attributes: this.context.phpAttributeMapper.convert({
-                        type: convertedType,
-                        property
-                    })
-                })
-            );
+            clazz.addField(this.toField({ property }));
+        }
+        for (const property of this.objectDeclaration.extendedProperties ?? []) {
+            clazz.addField(this.toField({ property, inherited: true }));
         }
 
         return new PhpFile({
@@ -51,6 +44,21 @@ export class ObjectGenerator extends FileGenerator<PhpFile, ModelCustomConfigSch
         });
     }
 
+    private toField({ property, inherited }: { property: ObjectProperty; inherited?: boolean }): php.Field {
+        const convertedType = this.context.phpTypeMapper.convert({ reference: property.valueType });
+        return php.field({
+            type: convertedType,
+            name: this.context.getPropertyName(property.name.name),
+            access: "public",
+            docs: property.docs,
+            attributes: this.context.phpAttributeMapper.convert({
+                type: convertedType,
+                property
+            }),
+            inherited
+        });
+    }
+
     protected getFilepath(): RelativeFilePath {
         return this.context.getLocationForTypeId(this.typeDeclaration.name.typeId).directory;
     }
diff --git a/generators/php/model/src/trait/TraitGenerator.ts b/generators/php/model/src/trait/TraitGenerator.ts
new file mode 100644
index 00000000000..e06ab5e80db
--- /dev/null
+++ b/generators/php/model/src/trait/TraitGenerator.ts
@@ -0,0 +1,58 @@
+import { join, RelativeFilePath } from "@fern-api/fs-utils";
+import { PhpFile } from "@fern-api/php-codegen";
+import { FileGenerator } from "@fern-api/php-codegen";
+import { php } from "@fern-api/php-codegen";
+import { ObjectTypeDeclaration, TypeDeclaration } from "@fern-fern/ir-sdk/api";
+import { ModelCustomConfigSchema } from "../ModelCustomConfig";
+import { ModelGeneratorContext } from "../ModelGeneratorContext";
+
+export class TraitGenerator extends FileGenerator<PhpFile, ModelCustomConfigSchema, ModelGeneratorContext> {
+    private readonly typeDeclaration: TypeDeclaration;
+    private readonly classReference: php.ClassReference;
+    constructor(
+        context: ModelGeneratorContext,
+        typeDeclaration: TypeDeclaration,
+        private readonly objectDeclaration: ObjectTypeDeclaration
+    ) {
+        super(context);
+        this.typeDeclaration = typeDeclaration;
+        this.classReference = this.context.phpTypeMapper.convertToTraitClassReference(this.typeDeclaration.name);
+    }
+
+    public doGenerate(): PhpFile {
+        const clazz = php.trait({
+            ...this.classReference,
+            docs: this.typeDeclaration.docs,
+            traits: this.objectDeclaration.extends.map((declaredTypeName) =>
+                this.context.phpTypeMapper.convertToTraitClassReference(declaredTypeName)
+            )
+        });
+
+        for (const property of this.objectDeclaration.properties) {
+            const convertedType = this.context.phpTypeMapper.convert({ reference: property.valueType });
+            clazz.addField(
+                php.field({
+                    type: convertedType,
+                    name: this.context.getPropertyName(property.name.name),
+                    access: "public",
+                    docs: property.docs,
+                    attributes: this.context.phpAttributeMapper.convert({
+                        type: convertedType,
+                        property
+                    })
+                })
+            );
+        }
+
+        return new PhpFile({
+            clazz,
+            rootNamespace: this.context.getRootNamespace(),
+            directory: this.context.getTraitLocationForTypeId(this.typeDeclaration.name.typeId).directory,
+            customConfig: this.context.customConfig
+        });
+    }
+
+    protected getFilepath(): RelativeFilePath {
+        return this.context.getTraitLocationForTypeId(this.typeDeclaration.name.typeId).directory;
+    }
+}
diff --git a/generators/php/sdk/src/SdkGeneratorCli.ts b/generators/php/sdk/src/SdkGeneratorCli.ts
index 31628921fdb..5c77b1f7dfe 100644
--- a/generators/php/sdk/src/SdkGeneratorCli.ts
+++ b/generators/php/sdk/src/SdkGeneratorCli.ts
@@ -4,7 +4,7 @@ import { FernGeneratorExec } from "@fern-fern/generator-exec-sdk";
 import { HttpService, IntermediateRepresentation } from "@fern-fern/ir-sdk/api";
 import { SdkCustomConfigSchema } from "./SdkCustomConfig";
 import { SdkGeneratorContext } from "./SdkGeneratorContext";
-import { generateModels } from "@fern-api/php-model";
+import { generateModels, generateTraits } from "@fern-api/php-model";
 import { RootClientGenerator } from "./root-client/RootClientGenerator";
 import { SubPackageClientGenerator } from "./subpackage-client/SubPackageClientGenerator";
 import { WrappedEndpointRequestGenerator } from "./endpoint/request/WrappedEndpointRequestGenerator";
@@ -49,6 +49,7 @@ export class SdkGeneratorCLI extends AbstractPhpGeneratorCli<SdkCustomConfigSche
 
     protected async generate(context: SdkGeneratorContext): Promise<void> {
         generateModels(context);
+        generateTraits(context);
         this.generateRootClient(context);
         this.generateSubpackages(context);
         this.generateEnvironment(context);
diff --git a/generators/php/sdk/src/endpoint/request/WrappedEndpointRequestGenerator.ts b/generators/php/sdk/src/endpoint/request/WrappedEndpointRequestGenerator.ts
index f25032cfa60..787fdf30b0c 100644
--- a/generators/php/sdk/src/endpoint/request/WrappedEndpointRequestGenerator.ts
+++ b/generators/php/sdk/src/endpoint/request/WrappedEndpointRequestGenerator.ts
@@ -1,6 +1,12 @@
 import { php, PhpFile, FileGenerator, FileLocation } from "@fern-api/php-codegen";
 import { join, RelativeFilePath } from "@fern-api/fs-utils";
-import { HttpEndpoint, SdkRequestWrapper, ServiceId } from "@fern-fern/ir-sdk/api";
+import {
+    HttpEndpoint,
+    InlinedRequestBodyProperty,
+    ObjectProperty,
+    SdkRequestWrapper,
+    ServiceId
+} from "@fern-fern/ir-sdk/api";
 import { SdkCustomConfigSchema } from "../../SdkCustomConfig";
 import { SdkGeneratorContext } from "../../SdkGeneratorContext";
 
@@ -78,16 +84,13 @@ export class WrappedEndpointRequestGenerator extends FileGenerator<
             },
             inlinedRequestBody: (request) => {
                 for (const property of request.properties) {
-                    const type = this.context.phpTypeMapper.convert({ reference: property.valueType });
-                    clazz.addField(
-                        php.field({
-                            name: this.context.getPropertyName(property.name.name),
-                            type,
-                            access: "public",
-                            docs: property.docs,
-                            attributes: this.context.phpAttributeMapper.convert({ type, property })
-                        })
-                    );
+                    clazz.addField(this.toField({ property }));
+                }
+                for (const property of request.extendedProperties ?? []) {
+                    clazz.addField(this.toField({ property, inherited: true }));
+                }
+                for (const declaredTypeName of request.extends) {
+                    clazz.addTrait(this.context.phpTypeMapper.convertToTraitClassReference(declaredTypeName));
                 }
             },
             fileUpload: () => undefined,
@@ -103,6 +106,21 @@ export class WrappedEndpointRequestGenerator extends FileGenerator<
         });
     }
 
+    private toField({ property, inherited }: { property: InlinedRequestBodyProperty; inherited?: boolean }): php.Field {
+        const convertedType = this.context.phpTypeMapper.convert({ reference: property.valueType });
+        return php.field({
+            type: convertedType,
+            name: this.context.getPropertyName(property.name.name),
+            access: "public",
+            docs: property.docs,
+            attributes: this.context.phpAttributeMapper.convert({
+                type: convertedType,
+                property
+            }),
+            inherited
+        });
+    }
+
     protected getFilepath(): RelativeFilePath {
         return join(
             this.context.project.filepaths.getSourceDirectory(),
diff --git a/generators/php/sdk/versions.yml b/generators/php/sdk/versions.yml
index c9a63e645a9..736c756accb 100644
--- a/generators/php/sdk/versions.yml
+++ b/generators/php/sdk/versions.yml
@@ -1,3 +1,8 @@
+- version: 0.1.6
+  changelogEntry:
+    - type: feat
+      summary: >-
+        Support inheritance for types and inlined requests.
 - version: 0.1.5
   changelogEntry:
     - type: feat
diff --git a/seed/php-model/alias-extends/src/Child.php b/seed/php-model/alias-extends/src/Child.php
index b8c31ff899d..7bee8fcda65 100644
--- a/seed/php-model/alias-extends/src/Child.php
+++ b/seed/php-model/alias-extends/src/Child.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Parent_;
 use Seed\Core\Json\JsonProperty;
 
 class Child extends SerializableType
 {
+    use Parent_;
+
     /**
      * @var string $child
      */
@@ -16,11 +19,13 @@ class Child extends SerializableType
     /**
      * @param array{
      *   child: string,
+     *   parent: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->child = $values['child'];
+        $this->parent = $values['parent'];
     }
 }
diff --git a/seed/php-model/alias-extends/src/Traits/AliasType.php b/seed/php-model/alias-extends/src/Traits/AliasType.php
new file mode 100644
index 00000000000..6ec816f3e3a
--- /dev/null
+++ b/seed/php-model/alias-extends/src/Traits/AliasType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait AliasType
+{
+    /**
+     * @var string $parent
+     */
+    #[JsonProperty('parent')]
+    public string $parent;
+}
diff --git a/seed/php-model/alias-extends/src/Traits/Parent_.php b/seed/php-model/alias-extends/src/Traits/Parent_.php
new file mode 100644
index 00000000000..2545c9f3ab2
--- /dev/null
+++ b/seed/php-model/alias-extends/src/Traits/Parent_.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Parent_
+{
+    /**
+     * @var string $parent
+     */
+    #[JsonProperty('parent')]
+    public string $parent;
+}
diff --git a/seed/php-model/alias-extends/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/alias-extends/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/alias-extends/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/alias/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/alias/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/alias/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/any-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/any-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/any-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/audiences/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/audiences/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/audiences/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/basic-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/basic-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/basic-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/bytes/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/bytes/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/bytes/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/circular-references-advanced/src/A/A.php b/seed/php-model/circular-references-advanced/src/A/A.php
index ad86a0bec70..4cb6b867841 100644
--- a/seed/php-model/circular-references-advanced/src/A/A.php
+++ b/seed/php-model/circular-references-advanced/src/A/A.php
@@ -3,7 +3,21 @@
 namespace Seed\A;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\RootType;
 
 class A extends SerializableType
 {
+    use RootType;
+
+
+    /**
+     * @param array{
+     *   s: string,
+     * } $values
+     */
+    public function __construct(
+        array $values,
+    ) {
+        $this->s = $values['s'];
+    }
 }
diff --git a/seed/php-model/circular-references-advanced/src/Traits/RootType.php b/seed/php-model/circular-references-advanced/src/Traits/RootType.php
new file mode 100644
index 00000000000..44f28a09118
--- /dev/null
+++ b/seed/php-model/circular-references-advanced/src/Traits/RootType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait RootType
+{
+    /**
+     * @var string $s
+     */
+    #[JsonProperty('s')]
+    public string $s;
+}
diff --git a/seed/php-model/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/circular-references/src/A/A.php b/seed/php-model/circular-references/src/A/A.php
index ad86a0bec70..4cb6b867841 100644
--- a/seed/php-model/circular-references/src/A/A.php
+++ b/seed/php-model/circular-references/src/A/A.php
@@ -3,7 +3,21 @@
 namespace Seed\A;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\RootType;
 
 class A extends SerializableType
 {
+    use RootType;
+
+
+    /**
+     * @param array{
+     *   s: string,
+     * } $values
+     */
+    public function __construct(
+        array $values,
+    ) {
+        $this->s = $values['s'];
+    }
 }
diff --git a/seed/php-model/circular-references/src/Traits/RootType.php b/seed/php-model/circular-references/src/Traits/RootType.php
new file mode 100644
index 00000000000..44f28a09118
--- /dev/null
+++ b/seed/php-model/circular-references/src/Traits/RootType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait RootType
+{
+    /**
+     * @var string $s
+     */
+    #[JsonProperty('s')]
+    public string $s;
+}
diff --git a/seed/php-model/circular-references/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/circular-references/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/circular-references/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/custom-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/custom-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/custom-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/enum/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/enum/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/enum/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/error-property/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/error-property/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/error-property/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/examples/src/Types/ExtendedMovie.php b/seed/php-model/examples/src/Types/ExtendedMovie.php
index 4c313c65c61..03ac0fe7d8a 100644
--- a/seed/php-model/examples/src/Types/ExtendedMovie.php
+++ b/seed/php-model/examples/src/Types/ExtendedMovie.php
@@ -3,11 +3,14 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Types\Traits\Movie;
 use Seed\Core\Json\JsonProperty;
 use Seed\Core\Types\ArrayType;
 
 class ExtendedMovie extends SerializableType
 {
+    use Movie;
+
     /**
      * @var array<string> $cast
      */
@@ -17,11 +20,31 @@ class ExtendedMovie extends SerializableType
     /**
      * @param array{
      *   cast: array<string>,
+     *   id: string,
+     *   prequel?: ?string,
+     *   title: string,
+     *   from: string,
+     *   rating: float,
+     *   type: string,
+     *   tag: string,
+     *   book?: ?string,
+     *   metadata: array<string, mixed>,
+     *   revenue: int,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->cast = $values['cast'];
+        $this->id = $values['id'];
+        $this->prequel = $values['prequel'] ?? null;
+        $this->title = $values['title'];
+        $this->from = $values['from'];
+        $this->rating = $values['rating'];
+        $this->type = $values['type'];
+        $this->tag = $values['tag'];
+        $this->book = $values['book'] ?? null;
+        $this->metadata = $values['metadata'];
+        $this->revenue = $values['revenue'];
     }
 }
diff --git a/seed/php-model/examples/src/Types/Traits/Movie.php b/seed/php-model/examples/src/Types/Traits/Movie.php
new file mode 100644
index 00000000000..2f40680e303
--- /dev/null
+++ b/seed/php-model/examples/src/Types/Traits/Movie.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Seed\Types\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait Movie
+{
+    /**
+     * @var string $id
+     */
+    #[JsonProperty('id')]
+    public string $id;
+
+    /**
+     * @var ?string $prequel
+     */
+    #[JsonProperty('prequel')]
+    public ?string $prequel;
+
+    /**
+     * @var string $title
+     */
+    #[JsonProperty('title')]
+    public string $title;
+
+    /**
+     * @var string $from
+     */
+    #[JsonProperty('from')]
+    public string $from;
+
+    /**
+     * @var float $rating The rating scale is one to five stars
+     */
+    #[JsonProperty('rating')]
+    public float $rating;
+
+    /**
+     * @var string $type
+     */
+    #[JsonProperty('type')]
+    public string $type;
+
+    /**
+     * @var string $tag
+     */
+    #[JsonProperty('tag')]
+    public string $tag;
+
+    /**
+     * @var ?string $book
+     */
+    #[JsonProperty('book')]
+    public ?string $book;
+
+    /**
+     * @var array<string, mixed> $metadata
+     */
+    #[JsonProperty('metadata'), ArrayType(['string' => 'mixed'])]
+    public array $metadata;
+
+    /**
+     * @var int $revenue
+     */
+    #[JsonProperty('revenue')]
+    public int $revenue;
+}
diff --git a/seed/php-model/examples/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/examples/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/examples/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/exhaustive/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/exhaustive/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/exhaustive/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/extends/src/ExampleType.php b/seed/php-model/extends/src/ExampleType.php
index 7bc916aea74..f1d3ea4de79 100644
--- a/seed/php-model/extends/src/ExampleType.php
+++ b/seed/php-model/extends/src/ExampleType.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Docs;
 use Seed\Core\Json\JsonProperty;
 
 class ExampleType extends SerializableType
 {
+    use Docs;
+
     /**
      * @var string $name
      */
@@ -16,11 +19,13 @@ class ExampleType extends SerializableType
     /**
      * @param array{
      *   name: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->name = $values['name'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-model/extends/src/Json.php b/seed/php-model/extends/src/Json.php
index 9bc11b9c494..c62a6c629f3 100644
--- a/seed/php-model/extends/src/Json.php
+++ b/seed/php-model/extends/src/Json.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Docs;
 use Seed\Core\Json\JsonProperty;
 
 class Json extends SerializableType
 {
+    use Docs;
+
     /**
      * @var string $raw
      */
@@ -16,11 +19,13 @@ class Json extends SerializableType
     /**
      * @param array{
      *   raw: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->raw = $values['raw'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-model/extends/src/NestedType.php b/seed/php-model/extends/src/NestedType.php
index 2955b61bdc5..74cecd3ca25 100644
--- a/seed/php-model/extends/src/NestedType.php
+++ b/seed/php-model/extends/src/NestedType.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Json;
 use Seed\Core\Json\JsonProperty;
 
 class NestedType extends SerializableType
 {
+    use Json;
+
     /**
      * @var string $name
      */
@@ -16,11 +19,15 @@ class NestedType extends SerializableType
     /**
      * @param array{
      *   name: string,
+     *   raw: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->name = $values['name'];
+        $this->raw = $values['raw'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-model/extends/src/Traits/Docs.php b/seed/php-model/extends/src/Traits/Docs.php
new file mode 100644
index 00000000000..17eaf8aa4ff
--- /dev/null
+++ b/seed/php-model/extends/src/Traits/Docs.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Docs
+{
+    /**
+     * @var string $docs
+     */
+    #[JsonProperty('docs')]
+    public string $docs;
+}
diff --git a/seed/php-model/extends/src/Traits/ExampleType.php b/seed/php-model/extends/src/Traits/ExampleType.php
new file mode 100644
index 00000000000..27f834f90d5
--- /dev/null
+++ b/seed/php-model/extends/src/Traits/ExampleType.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait ExampleType
+{
+    use Docs;
+
+    /**
+     * @var string $name
+     */
+    #[JsonProperty('name')]
+    public string $name;
+}
diff --git a/seed/php-model/extends/src/Traits/Json.php b/seed/php-model/extends/src/Traits/Json.php
new file mode 100644
index 00000000000..dcd46c8a1f1
--- /dev/null
+++ b/seed/php-model/extends/src/Traits/Json.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Json
+{
+    use Docs;
+
+    /**
+     * @var string $raw
+     */
+    #[JsonProperty('raw')]
+    public string $raw;
+}
diff --git a/seed/php-model/extends/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/extends/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/extends/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/extra-properties/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/extra-properties/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/extra-properties/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/file-download/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/file-download/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/file-download/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/file-upload/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/file-upload/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/file-upload/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/folders/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/folders/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/folders/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/grpc-proto/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/grpc-proto/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/grpc-proto/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/idempotency-headers/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/idempotency-headers/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/idempotency-headers/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/imdb/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/imdb/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/imdb/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/literal/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/literal/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/literal/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/mixed-case/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/mixed-case/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/mixed-case/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/multi-line-docs/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/multi-line-docs/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/multi-line-docs/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/multi-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/multi-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/multi-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/multi-url-environment/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/multi-url-environment/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/multi-url-environment/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/no-environment/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/no-environment/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/no-environment/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/object/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/object/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/object/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/objects-with-imports/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/objects-with-imports/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/objects-with-imports/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/optional/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/optional/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/optional/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/package-yml/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/package-yml/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/package-yml/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/pagination/src/Users/ListUsersExtendedOptionalListResponse.php b/seed/php-model/pagination/src/Users/ListUsersExtendedOptionalListResponse.php
index 00810b43f46..e454dd175bf 100644
--- a/seed/php-model/pagination/src/Users/ListUsersExtendedOptionalListResponse.php
+++ b/seed/php-model/pagination/src/Users/ListUsersExtendedOptionalListResponse.php
@@ -3,10 +3,13 @@
 namespace Seed\Users;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Users\Traits\UserOptionalListPage;
 use Seed\Core\Json\JsonProperty;
 
 class ListUsersExtendedOptionalListResponse extends SerializableType
 {
+    use UserOptionalListPage;
+
     /**
      * @var int $totalCount The totall number of /users
      */
@@ -16,11 +19,15 @@ class ListUsersExtendedOptionalListResponse extends SerializableType
     /**
      * @param array{
      *   totalCount: int,
+     *   data: UserOptionalListContainer,
+     *   next?: ?string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->totalCount = $values['totalCount'];
+        $this->data = $values['data'];
+        $this->next = $values['next'] ?? null;
     }
 }
diff --git a/seed/php-model/pagination/src/Users/ListUsersExtendedResponse.php b/seed/php-model/pagination/src/Users/ListUsersExtendedResponse.php
index dc600ccd164..93df8c38ec8 100644
--- a/seed/php-model/pagination/src/Users/ListUsersExtendedResponse.php
+++ b/seed/php-model/pagination/src/Users/ListUsersExtendedResponse.php
@@ -3,10 +3,13 @@
 namespace Seed\Users;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Users\Traits\UserPage;
 use Seed\Core\Json\JsonProperty;
 
 class ListUsersExtendedResponse extends SerializableType
 {
+    use UserPage;
+
     /**
      * @var int $totalCount The totall number of /users
      */
@@ -16,11 +19,15 @@ class ListUsersExtendedResponse extends SerializableType
     /**
      * @param array{
      *   totalCount: int,
+     *   data: UserListContainer,
+     *   next?: ?string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->totalCount = $values['totalCount'];
+        $this->data = $values['data'];
+        $this->next = $values['next'] ?? null;
     }
 }
diff --git a/seed/php-model/pagination/src/Users/Traits/UserOptionalListPage.php b/seed/php-model/pagination/src/Users/Traits/UserOptionalListPage.php
new file mode 100644
index 00000000000..3056830dc17
--- /dev/null
+++ b/seed/php-model/pagination/src/Users/Traits/UserOptionalListPage.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Users\Traits;
+
+use Seed\Users\UserOptionalListContainer;
+use Seed\Core\Json\JsonProperty;
+
+trait UserOptionalListPage
+{
+    /**
+     * @var UserOptionalListContainer $data
+     */
+    #[JsonProperty('data')]
+    public UserOptionalListContainer $data;
+
+    /**
+     * @var ?string $next
+     */
+    #[JsonProperty('next')]
+    public ?string $next;
+}
diff --git a/seed/php-model/pagination/src/Users/Traits/UserPage.php b/seed/php-model/pagination/src/Users/Traits/UserPage.php
new file mode 100644
index 00000000000..2a14493a98e
--- /dev/null
+++ b/seed/php-model/pagination/src/Users/Traits/UserPage.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Users\Traits;
+
+use Seed\Users\UserListContainer;
+use Seed\Core\Json\JsonProperty;
+
+trait UserPage
+{
+    /**
+     * @var UserListContainer $data
+     */
+    #[JsonProperty('data')]
+    public UserListContainer $data;
+
+    /**
+     * @var ?string $next
+     */
+    #[JsonProperty('next')]
+    public ?string $next;
+}
diff --git a/seed/php-model/pagination/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/pagination/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/pagination/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/plain-text/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/plain-text/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/plain-text/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/query-parameters/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/query-parameters/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/query-parameters/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/reserved-keywords/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/reserved-keywords/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/reserved-keywords/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/response-property/src/Service/Response.php b/seed/php-model/response-property/src/Service/Response.php
index 46eaf9deee5..ec80232ba7a 100644
--- a/seed/php-model/response-property/src/Service/Response.php
+++ b/seed/php-model/response-property/src/Service/Response.php
@@ -3,10 +3,15 @@
 namespace Seed\Service;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\WithMetadata;
+use Seed\Service\Traits\WithDocs;
 use Seed\Core\Json\JsonProperty;
 
 class Response extends SerializableType
 {
+    use WithMetadata;
+    use WithDocs;
+
     /**
      * @var Movie $data
      */
@@ -16,11 +21,15 @@ class Response extends SerializableType
     /**
      * @param array{
      *   data: Movie,
+     *   metadata: array<string, string>,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->data = $values['data'];
+        $this->metadata = $values['metadata'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-model/response-property/src/Service/Traits/WithDocs.php b/seed/php-model/response-property/src/Service/Traits/WithDocs.php
new file mode 100644
index 00000000000..429bb4dd850
--- /dev/null
+++ b/seed/php-model/response-property/src/Service/Traits/WithDocs.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Service\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait WithDocs
+{
+    /**
+     * @var string $docs
+     */
+    #[JsonProperty('docs')]
+    public string $docs;
+}
diff --git a/seed/php-model/response-property/src/Traits/WithMetadata.php b/seed/php-model/response-property/src/Traits/WithMetadata.php
new file mode 100644
index 00000000000..af6dc5a7ffc
--- /dev/null
+++ b/seed/php-model/response-property/src/Traits/WithMetadata.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait WithMetadata
+{
+    /**
+     * @var array<string, string> $metadata
+     */
+    #[JsonProperty('metadata'), ArrayType(['string' => 'string'])]
+    public array $metadata;
+}
diff --git a/seed/php-model/response-property/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/response-property/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/response-property/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/server-sent-events/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/server-sent-events/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/server-sent-events/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/simple-fhir/src/Account.php b/seed/php-model/simple-fhir/src/Account.php
index d845b0822f6..422d2ee66b5 100644
--- a/seed/php-model/simple-fhir/src/Account.php
+++ b/seed/php-model/simple-fhir/src/Account.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Account extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -37,6 +40,9 @@ class Account extends SerializableType
      *   name: string,
      *   patient?: ?Patient,
      *   practitioner?: ?Practitioner,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -46,5 +52,8 @@ public function __construct(
         $this->name = $values['name'];
         $this->patient = $values['patient'] ?? null;
         $this->practitioner = $values['practitioner'] ?? null;
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-model/simple-fhir/src/Patient.php b/seed/php-model/simple-fhir/src/Patient.php
index 277551e5508..bb245c25d64 100644
--- a/seed/php-model/simple-fhir/src/Patient.php
+++ b/seed/php-model/simple-fhir/src/Patient.php
@@ -3,11 +3,14 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 use Seed\Core\Types\ArrayType;
 
 class Patient extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -31,6 +34,9 @@ class Patient extends SerializableType
      *   resourceType: string,
      *   name: string,
      *   scripts: array<Script>,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -39,5 +45,8 @@ public function __construct(
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
         $this->scripts = $values['scripts'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-model/simple-fhir/src/Practitioner.php b/seed/php-model/simple-fhir/src/Practitioner.php
index 708896e88be..91290e6629b 100644
--- a/seed/php-model/simple-fhir/src/Practitioner.php
+++ b/seed/php-model/simple-fhir/src/Practitioner.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Practitioner extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -23,6 +26,9 @@ class Practitioner extends SerializableType
      * @param array{
      *   resourceType: string,
      *   name: string,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -30,5 +36,8 @@ public function __construct(
     ) {
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-model/simple-fhir/src/Script.php b/seed/php-model/simple-fhir/src/Script.php
index 088cbeaaad8..ec598e034d3 100644
--- a/seed/php-model/simple-fhir/src/Script.php
+++ b/seed/php-model/simple-fhir/src/Script.php
@@ -3,10 +3,13 @@
 namespace Seed;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Script extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -23,6 +26,9 @@ class Script extends SerializableType
      * @param array{
      *   resourceType: string,
      *   name: string,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -30,5 +36,8 @@ public function __construct(
     ) {
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-model/simple-fhir/src/Traits/BaseResource.php b/seed/php-model/simple-fhir/src/Traits/BaseResource.php
new file mode 100644
index 00000000000..86b5045a19f
--- /dev/null
+++ b/seed/php-model/simple-fhir/src/Traits/BaseResource.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Account;
+use Seed\Patient;
+use Seed\Practitioner;
+use Seed\Script;
+use Seed\Core\Types\ArrayType;
+use Seed\Core\Types\Union;
+use Seed\Memo;
+
+trait BaseResource
+{
+    /**
+     * @var string $id
+     */
+    #[JsonProperty('id')]
+    public string $id;
+
+    /**
+     * @var array<Account|Patient|Practitioner|Script> $relatedResources
+     */
+    #[JsonProperty('related_resources'), ArrayType([new Union(Account::class, Patient::class, Practitioner::class, Script::class)])]
+    public array $relatedResources;
+
+    /**
+     * @var Memo $memo
+     */
+    #[JsonProperty('memo')]
+    public Memo $memo;
+}
diff --git a/seed/php-model/simple-fhir/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/simple-fhir/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/simple-fhir/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/streaming-parameter/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/streaming-parameter/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/streaming-parameter/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/streaming/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/streaming/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/streaming/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/trace/src/Playlist/Playlist.php b/seed/php-model/trace/src/Playlist/Playlist.php
index b5d0680e3c9..20e2d6dd5d7 100644
--- a/seed/php-model/trace/src/Playlist/Playlist.php
+++ b/seed/php-model/trace/src/Playlist/Playlist.php
@@ -3,10 +3,13 @@
 namespace Seed\Playlist;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Playlist\Traits\PlaylistCreateRequest;
 use Seed\Core\Json\JsonProperty;
 
 class Playlist extends SerializableType
 {
+    use PlaylistCreateRequest;
+
     /**
      * @var string $playlistId
      */
@@ -23,6 +26,8 @@ class Playlist extends SerializableType
      * @param array{
      *   playlistId: string,
      *   ownerId: string,
+     *   name: string,
+     *   problems: array<string>,
      * } $values
      */
     public function __construct(
@@ -30,5 +35,7 @@ public function __construct(
     ) {
         $this->playlistId = $values['playlistId'];
         $this->ownerId = $values['ownerId'];
+        $this->name = $values['name'];
+        $this->problems = $values['problems'];
     }
 }
diff --git a/seed/php-model/trace/src/Playlist/Traits/PlaylistCreateRequest.php b/seed/php-model/trace/src/Playlist/Traits/PlaylistCreateRequest.php
new file mode 100644
index 00000000000..3dd5b623fa7
--- /dev/null
+++ b/seed/php-model/trace/src/Playlist/Traits/PlaylistCreateRequest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Playlist\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait PlaylistCreateRequest
+{
+    /**
+     * @var string $name
+     */
+    #[JsonProperty('name')]
+    public string $name;
+
+    /**
+     * @var array<string> $problems
+     */
+    #[JsonProperty('problems'), ArrayType(['string'])]
+    public array $problems;
+}
diff --git a/seed/php-model/trace/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/trace/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/trace/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/unions/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/unions/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/unions/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/unknown/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/unknown/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/unknown/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/validation/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/validation/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/validation/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/version-no-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/version-no-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/version-no-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/version/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/version/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/version/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-model/websocket/tests/Seed/Core/Json/TraitTest.php b/seed/php-model/websocket/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-model/websocket/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/alias-extends/src/Requests/InlinedChildRequest.php b/seed/php-sdk/alias-extends/src/Requests/InlinedChildRequest.php
index e1f0d3fbf7d..956fa09d1b1 100644
--- a/seed/php-sdk/alias-extends/src/Requests/InlinedChildRequest.php
+++ b/seed/php-sdk/alias-extends/src/Requests/InlinedChildRequest.php
@@ -3,10 +3,13 @@
 namespace Seed\Requests;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\AliasType;
 use Seed\Core\Json\JsonProperty;
 
 class InlinedChildRequest extends SerializableType
 {
+    use AliasType;
+
     /**
      * @var string $child
      */
@@ -16,11 +19,13 @@ class InlinedChildRequest extends SerializableType
     /**
      * @param array{
      *   child: string,
+     *   parent: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->child = $values['child'];
+        $this->parent = $values['parent'];
     }
 }
diff --git a/seed/php-sdk/alias-extends/src/Traits/AliasType.php b/seed/php-sdk/alias-extends/src/Traits/AliasType.php
new file mode 100644
index 00000000000..6ec816f3e3a
--- /dev/null
+++ b/seed/php-sdk/alias-extends/src/Traits/AliasType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait AliasType
+{
+    /**
+     * @var string $parent
+     */
+    #[JsonProperty('parent')]
+    public string $parent;
+}
diff --git a/seed/php-sdk/alias-extends/src/Traits/Parent_.php b/seed/php-sdk/alias-extends/src/Traits/Parent_.php
new file mode 100644
index 00000000000..2545c9f3ab2
--- /dev/null
+++ b/seed/php-sdk/alias-extends/src/Traits/Parent_.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Parent_
+{
+    /**
+     * @var string $parent
+     */
+    #[JsonProperty('parent')]
+    public string $parent;
+}
diff --git a/seed/php-sdk/alias-extends/src/Types/Child.php b/seed/php-sdk/alias-extends/src/Types/Child.php
index e31712505bc..50017902786 100644
--- a/seed/php-sdk/alias-extends/src/Types/Child.php
+++ b/seed/php-sdk/alias-extends/src/Types/Child.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Parent_;
 use Seed\Core\Json\JsonProperty;
 
 class Child extends SerializableType
 {
+    use Parent_;
+
     /**
      * @var string $child
      */
@@ -16,11 +19,13 @@ class Child extends SerializableType
     /**
      * @param array{
      *   child: string,
+     *   parent: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->child = $values['child'];
+        $this->parent = $values['parent'];
     }
 }
diff --git a/seed/php-sdk/alias-extends/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/alias-extends/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/alias-extends/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/alias/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/alias/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/alias/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/any-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/any-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/any-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/api-wide-base-path/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/audiences/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/audiences/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/audiences/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/basic-auth-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/basic-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/basic-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/basic-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/bearer-token-environment-variable/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/bytes/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/bytes/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/bytes/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/circular-references-advanced/src/A/Types/A.php b/seed/php-sdk/circular-references-advanced/src/A/Types/A.php
index 5151cd85775..fe81f24ee8e 100644
--- a/seed/php-sdk/circular-references-advanced/src/A/Types/A.php
+++ b/seed/php-sdk/circular-references-advanced/src/A/Types/A.php
@@ -3,7 +3,21 @@
 namespace Seed\A\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\RootType;
 
 class A extends SerializableType
 {
+    use RootType;
+
+
+    /**
+     * @param array{
+     *   s: string,
+     * } $values
+     */
+    public function __construct(
+        array $values,
+    ) {
+        $this->s = $values['s'];
+    }
 }
diff --git a/seed/php-sdk/circular-references-advanced/src/Traits/RootType.php b/seed/php-sdk/circular-references-advanced/src/Traits/RootType.php
new file mode 100644
index 00000000000..44f28a09118
--- /dev/null
+++ b/seed/php-sdk/circular-references-advanced/src/Traits/RootType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait RootType
+{
+    /**
+     * @var string $s
+     */
+    #[JsonProperty('s')]
+    public string $s;
+}
diff --git a/seed/php-sdk/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/circular-references-advanced/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/circular-references/src/A/Types/A.php b/seed/php-sdk/circular-references/src/A/Types/A.php
index 5151cd85775..fe81f24ee8e 100644
--- a/seed/php-sdk/circular-references/src/A/Types/A.php
+++ b/seed/php-sdk/circular-references/src/A/Types/A.php
@@ -3,7 +3,21 @@
 namespace Seed\A\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\RootType;
 
 class A extends SerializableType
 {
+    use RootType;
+
+
+    /**
+     * @param array{
+     *   s: string,
+     * } $values
+     */
+    public function __construct(
+        array $values,
+    ) {
+        $this->s = $values['s'];
+    }
 }
diff --git a/seed/php-sdk/circular-references/src/Traits/RootType.php b/seed/php-sdk/circular-references/src/Traits/RootType.php
new file mode 100644
index 00000000000..44f28a09118
--- /dev/null
+++ b/seed/php-sdk/circular-references/src/Traits/RootType.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait RootType
+{
+    /**
+     * @var string $s
+     */
+    #[JsonProperty('s')]
+    public string $s;
+}
diff --git a/seed/php-sdk/circular-references/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/circular-references/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/circular-references/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/cross-package-type-names/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/custom-auth/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/custom-auth/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/custom-auth/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/enum/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/enum/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/enum/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/error-property/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/error-property/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/error-property/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/examples/src/Types/Traits/Movie.php b/seed/php-sdk/examples/src/Types/Traits/Movie.php
new file mode 100644
index 00000000000..2f40680e303
--- /dev/null
+++ b/seed/php-sdk/examples/src/Types/Traits/Movie.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Seed\Types\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait Movie
+{
+    /**
+     * @var string $id
+     */
+    #[JsonProperty('id')]
+    public string $id;
+
+    /**
+     * @var ?string $prequel
+     */
+    #[JsonProperty('prequel')]
+    public ?string $prequel;
+
+    /**
+     * @var string $title
+     */
+    #[JsonProperty('title')]
+    public string $title;
+
+    /**
+     * @var string $from
+     */
+    #[JsonProperty('from')]
+    public string $from;
+
+    /**
+     * @var float $rating The rating scale is one to five stars
+     */
+    #[JsonProperty('rating')]
+    public float $rating;
+
+    /**
+     * @var string $type
+     */
+    #[JsonProperty('type')]
+    public string $type;
+
+    /**
+     * @var string $tag
+     */
+    #[JsonProperty('tag')]
+    public string $tag;
+
+    /**
+     * @var ?string $book
+     */
+    #[JsonProperty('book')]
+    public ?string $book;
+
+    /**
+     * @var array<string, mixed> $metadata
+     */
+    #[JsonProperty('metadata'), ArrayType(['string' => 'mixed'])]
+    public array $metadata;
+
+    /**
+     * @var int $revenue
+     */
+    #[JsonProperty('revenue')]
+    public int $revenue;
+}
diff --git a/seed/php-sdk/examples/src/Types/Types/ExtendedMovie.php b/seed/php-sdk/examples/src/Types/Types/ExtendedMovie.php
index 53833254891..cfb47ab6434 100644
--- a/seed/php-sdk/examples/src/Types/Types/ExtendedMovie.php
+++ b/seed/php-sdk/examples/src/Types/Types/ExtendedMovie.php
@@ -3,11 +3,14 @@
 namespace Seed\Types\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Types\Traits\Movie;
 use Seed\Core\Json\JsonProperty;
 use Seed\Core\Types\ArrayType;
 
 class ExtendedMovie extends SerializableType
 {
+    use Movie;
+
     /**
      * @var array<string> $cast
      */
@@ -17,11 +20,31 @@ class ExtendedMovie extends SerializableType
     /**
      * @param array{
      *   cast: array<string>,
+     *   id: string,
+     *   prequel?: ?string,
+     *   title: string,
+     *   from: string,
+     *   rating: float,
+     *   type: string,
+     *   tag: string,
+     *   book?: ?string,
+     *   metadata: array<string, mixed>,
+     *   revenue: int,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->cast = $values['cast'];
+        $this->id = $values['id'];
+        $this->prequel = $values['prequel'] ?? null;
+        $this->title = $values['title'];
+        $this->from = $values['from'];
+        $this->rating = $values['rating'];
+        $this->type = $values['type'];
+        $this->tag = $values['tag'];
+        $this->book = $values['book'] ?? null;
+        $this->metadata = $values['metadata'];
+        $this->revenue = $values['revenue'];
     }
 }
diff --git a/seed/php-sdk/examples/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/examples/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/examples/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/exhaustive/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/exhaustive/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/exhaustive/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/extends/src/Requests/Inlined.php b/seed/php-sdk/extends/src/Requests/Inlined.php
index 3604e4273f5..73e4cca0224 100644
--- a/seed/php-sdk/extends/src/Requests/Inlined.php
+++ b/seed/php-sdk/extends/src/Requests/Inlined.php
@@ -3,10 +3,13 @@
 namespace Seed\Requests;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\ExampleType;
 use Seed\Core\Json\JsonProperty;
 
 class Inlined extends SerializableType
 {
+    use ExampleType;
+
     /**
      * @var string $unique
      */
@@ -16,11 +19,15 @@ class Inlined extends SerializableType
     /**
      * @param array{
      *   unique: string,
+     *   name: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->unique = $values['unique'];
+        $this->name = $values['name'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-sdk/extends/src/Traits/Docs.php b/seed/php-sdk/extends/src/Traits/Docs.php
new file mode 100644
index 00000000000..17eaf8aa4ff
--- /dev/null
+++ b/seed/php-sdk/extends/src/Traits/Docs.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Docs
+{
+    /**
+     * @var string $docs
+     */
+    #[JsonProperty('docs')]
+    public string $docs;
+}
diff --git a/seed/php-sdk/extends/src/Traits/ExampleType.php b/seed/php-sdk/extends/src/Traits/ExampleType.php
new file mode 100644
index 00000000000..27f834f90d5
--- /dev/null
+++ b/seed/php-sdk/extends/src/Traits/ExampleType.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait ExampleType
+{
+    use Docs;
+
+    /**
+     * @var string $name
+     */
+    #[JsonProperty('name')]
+    public string $name;
+}
diff --git a/seed/php-sdk/extends/src/Traits/Json.php b/seed/php-sdk/extends/src/Traits/Json.php
new file mode 100644
index 00000000000..dcd46c8a1f1
--- /dev/null
+++ b/seed/php-sdk/extends/src/Traits/Json.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait Json
+{
+    use Docs;
+
+    /**
+     * @var string $raw
+     */
+    #[JsonProperty('raw')]
+    public string $raw;
+}
diff --git a/seed/php-sdk/extends/src/Types/ExampleType.php b/seed/php-sdk/extends/src/Types/ExampleType.php
index a4fc3727361..9cb80ffd1d7 100644
--- a/seed/php-sdk/extends/src/Types/ExampleType.php
+++ b/seed/php-sdk/extends/src/Types/ExampleType.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Docs;
 use Seed\Core\Json\JsonProperty;
 
 class ExampleType extends SerializableType
 {
+    use Docs;
+
     /**
      * @var string $name
      */
@@ -16,11 +19,13 @@ class ExampleType extends SerializableType
     /**
      * @param array{
      *   name: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->name = $values['name'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-sdk/extends/src/Types/Json.php b/seed/php-sdk/extends/src/Types/Json.php
index 0d77f46baa0..979b58ef40a 100644
--- a/seed/php-sdk/extends/src/Types/Json.php
+++ b/seed/php-sdk/extends/src/Types/Json.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Docs;
 use Seed\Core\Json\JsonProperty;
 
 class Json extends SerializableType
 {
+    use Docs;
+
     /**
      * @var string $raw
      */
@@ -16,11 +19,13 @@ class Json extends SerializableType
     /**
      * @param array{
      *   raw: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->raw = $values['raw'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-sdk/extends/src/Types/NestedType.php b/seed/php-sdk/extends/src/Types/NestedType.php
index 54528cc85b4..ecad7c3d0b7 100644
--- a/seed/php-sdk/extends/src/Types/NestedType.php
+++ b/seed/php-sdk/extends/src/Types/NestedType.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\Json;
 use Seed\Core\Json\JsonProperty;
 
 class NestedType extends SerializableType
 {
+    use Json;
+
     /**
      * @var string $name
      */
@@ -16,11 +19,15 @@ class NestedType extends SerializableType
     /**
      * @param array{
      *   name: string,
+     *   raw: string,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->name = $values['name'];
+        $this->raw = $values['raw'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-sdk/extends/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/extends/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/extends/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/extra-properties/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/extra-properties/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/extra-properties/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/file-download/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/file-download/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/file-download/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/file-upload/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/file-upload/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/file-upload/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/folders/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/folders/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/folders/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/grpc-proto-exhaustive/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/grpc-proto/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/grpc-proto/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/grpc-proto/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/idempotency-headers/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/idempotency-headers/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/idempotency-headers/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/imdb/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/imdb/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/imdb/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/literal/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/literal/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/literal/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/mixed-case/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/mixed-case/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/mixed-case/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/mixed-file-directory/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/multi-line-docs/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/multi-line-docs/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/multi-line-docs/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/no-environment/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/no-environment/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/no-environment/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/oauth-client-credentials-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/oauth-client-credentials-environment-variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/oauth-client-credentials-nested-root/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/oauth-client-credentials/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/object/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/object/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/object/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/objects-with-imports/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/objects-with-imports/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/objects-with-imports/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/optional/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/optional/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/optional/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/package-yml/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/package-yml/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/package-yml/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/pagination/src/Users/Traits/UserOptionalListPage.php b/seed/php-sdk/pagination/src/Users/Traits/UserOptionalListPage.php
new file mode 100644
index 00000000000..cec3f65b79c
--- /dev/null
+++ b/seed/php-sdk/pagination/src/Users/Traits/UserOptionalListPage.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Users\Traits;
+
+use Seed\Users\Types\UserOptionalListContainer;
+use Seed\Core\Json\JsonProperty;
+
+trait UserOptionalListPage
+{
+    /**
+     * @var UserOptionalListContainer $data
+     */
+    #[JsonProperty('data')]
+    public UserOptionalListContainer $data;
+
+    /**
+     * @var ?string $next
+     */
+    #[JsonProperty('next')]
+    public ?string $next;
+}
diff --git a/seed/php-sdk/pagination/src/Users/Traits/UserPage.php b/seed/php-sdk/pagination/src/Users/Traits/UserPage.php
new file mode 100644
index 00000000000..1f142e511c0
--- /dev/null
+++ b/seed/php-sdk/pagination/src/Users/Traits/UserPage.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Users\Traits;
+
+use Seed\Users\Types\UserListContainer;
+use Seed\Core\Json\JsonProperty;
+
+trait UserPage
+{
+    /**
+     * @var UserListContainer $data
+     */
+    #[JsonProperty('data')]
+    public UserListContainer $data;
+
+    /**
+     * @var ?string $next
+     */
+    #[JsonProperty('next')]
+    public ?string $next;
+}
diff --git a/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedOptionalListResponse.php b/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedOptionalListResponse.php
index 5866b827cb1..8ffe8f69969 100644
--- a/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedOptionalListResponse.php
+++ b/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedOptionalListResponse.php
@@ -3,10 +3,13 @@
 namespace Seed\Users\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Users\Traits\UserOptionalListPage;
 use Seed\Core\Json\JsonProperty;
 
 class ListUsersExtendedOptionalListResponse extends SerializableType
 {
+    use UserOptionalListPage;
+
     /**
      * @var int $totalCount The totall number of /users
      */
@@ -16,11 +19,15 @@ class ListUsersExtendedOptionalListResponse extends SerializableType
     /**
      * @param array{
      *   totalCount: int,
+     *   data: UserOptionalListContainer,
+     *   next?: ?string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->totalCount = $values['totalCount'];
+        $this->data = $values['data'];
+        $this->next = $values['next'] ?? null;
     }
 }
diff --git a/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedResponse.php b/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedResponse.php
index 2629506d6ee..b62f7dbeb81 100644
--- a/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedResponse.php
+++ b/seed/php-sdk/pagination/src/Users/Types/ListUsersExtendedResponse.php
@@ -3,10 +3,13 @@
 namespace Seed\Users\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Users\Traits\UserPage;
 use Seed\Core\Json\JsonProperty;
 
 class ListUsersExtendedResponse extends SerializableType
 {
+    use UserPage;
+
     /**
      * @var int $totalCount The totall number of /users
      */
@@ -16,11 +19,15 @@ class ListUsersExtendedResponse extends SerializableType
     /**
      * @param array{
      *   totalCount: int,
+     *   data: UserListContainer,
+     *   next?: ?string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->totalCount = $values['totalCount'];
+        $this->data = $values['data'];
+        $this->next = $values['next'] ?? null;
     }
 }
diff --git a/seed/php-sdk/pagination/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/pagination/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/pagination/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/plain-text/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/plain-text/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/plain-text/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/query-parameters/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/query-parameters/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/query-parameters/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/reserved-keywords/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/reserved-keywords/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/reserved-keywords/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/response-property/src/Service/Traits/WithDocs.php b/seed/php-sdk/response-property/src/Service/Traits/WithDocs.php
new file mode 100644
index 00000000000..429bb4dd850
--- /dev/null
+++ b/seed/php-sdk/response-property/src/Service/Traits/WithDocs.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Seed\Service\Traits;
+
+use Seed\Core\Json\JsonProperty;
+
+trait WithDocs
+{
+    /**
+     * @var string $docs
+     */
+    #[JsonProperty('docs')]
+    public string $docs;
+}
diff --git a/seed/php-sdk/response-property/src/Service/Types/Response.php b/seed/php-sdk/response-property/src/Service/Types/Response.php
index 31d797461f5..390c0432736 100644
--- a/seed/php-sdk/response-property/src/Service/Types/Response.php
+++ b/seed/php-sdk/response-property/src/Service/Types/Response.php
@@ -3,10 +3,15 @@
 namespace Seed\Service\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\WithMetadata;
+use Seed\Service\Traits\WithDocs;
 use Seed\Core\Json\JsonProperty;
 
 class Response extends SerializableType
 {
+    use WithMetadata;
+    use WithDocs;
+
     /**
      * @var Movie $data
      */
@@ -16,11 +21,15 @@ class Response extends SerializableType
     /**
      * @param array{
      *   data: Movie,
+     *   metadata: array<string, string>,
+     *   docs: string,
      * } $values
      */
     public function __construct(
         array $values,
     ) {
         $this->data = $values['data'];
+        $this->metadata = $values['metadata'];
+        $this->docs = $values['docs'];
     }
 }
diff --git a/seed/php-sdk/response-property/src/Traits/WithMetadata.php b/seed/php-sdk/response-property/src/Traits/WithMetadata.php
new file mode 100644
index 00000000000..af6dc5a7ffc
--- /dev/null
+++ b/seed/php-sdk/response-property/src/Traits/WithMetadata.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait WithMetadata
+{
+    /**
+     * @var array<string, string> $metadata
+     */
+    #[JsonProperty('metadata'), ArrayType(['string' => 'string'])]
+    public array $metadata;
+}
diff --git a/seed/php-sdk/response-property/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/response-property/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/response-property/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/server-sent-event-examples/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/server-sent-events/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/server-sent-events/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/server-sent-events/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/simple-fhir/src/Traits/BaseResource.php b/seed/php-sdk/simple-fhir/src/Traits/BaseResource.php
new file mode 100644
index 00000000000..d7885d64703
--- /dev/null
+++ b/seed/php-sdk/simple-fhir/src/Traits/BaseResource.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Seed\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Types\Account;
+use Seed\Types\Patient;
+use Seed\Types\Practitioner;
+use Seed\Types\Script;
+use Seed\Core\Types\ArrayType;
+use Seed\Core\Types\Union;
+use Seed\Types\Memo;
+
+trait BaseResource
+{
+    /**
+     * @var string $id
+     */
+    #[JsonProperty('id')]
+    public string $id;
+
+    /**
+     * @var array<Account|Patient|Practitioner|Script> $relatedResources
+     */
+    #[JsonProperty('related_resources'), ArrayType([new Union(Account::class, Patient::class, Practitioner::class, Script::class)])]
+    public array $relatedResources;
+
+    /**
+     * @var Memo $memo
+     */
+    #[JsonProperty('memo')]
+    public Memo $memo;
+}
diff --git a/seed/php-sdk/simple-fhir/src/Types/Account.php b/seed/php-sdk/simple-fhir/src/Types/Account.php
index 9163fd31a80..e16f2eaf4a1 100644
--- a/seed/php-sdk/simple-fhir/src/Types/Account.php
+++ b/seed/php-sdk/simple-fhir/src/Types/Account.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Account extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -37,6 +40,9 @@ class Account extends SerializableType
      *   name: string,
      *   patient?: ?Patient,
      *   practitioner?: ?Practitioner,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -46,5 +52,8 @@ public function __construct(
         $this->name = $values['name'];
         $this->patient = $values['patient'] ?? null;
         $this->practitioner = $values['practitioner'] ?? null;
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-sdk/simple-fhir/src/Types/Patient.php b/seed/php-sdk/simple-fhir/src/Types/Patient.php
index 5d032c76351..638138bde1a 100644
--- a/seed/php-sdk/simple-fhir/src/Types/Patient.php
+++ b/seed/php-sdk/simple-fhir/src/Types/Patient.php
@@ -3,11 +3,14 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 use Seed\Core\Types\ArrayType;
 
 class Patient extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -31,6 +34,9 @@ class Patient extends SerializableType
      *   resourceType: string,
      *   name: string,
      *   scripts: array<Script>,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -39,5 +45,8 @@ public function __construct(
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
         $this->scripts = $values['scripts'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-sdk/simple-fhir/src/Types/Practitioner.php b/seed/php-sdk/simple-fhir/src/Types/Practitioner.php
index 6ac780ddfaf..35c8337bac3 100644
--- a/seed/php-sdk/simple-fhir/src/Types/Practitioner.php
+++ b/seed/php-sdk/simple-fhir/src/Types/Practitioner.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Practitioner extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -23,6 +26,9 @@ class Practitioner extends SerializableType
      * @param array{
      *   resourceType: string,
      *   name: string,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -30,5 +36,8 @@ public function __construct(
     ) {
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-sdk/simple-fhir/src/Types/Script.php b/seed/php-sdk/simple-fhir/src/Types/Script.php
index 28b3c5df2b3..9603ca6ed12 100644
--- a/seed/php-sdk/simple-fhir/src/Types/Script.php
+++ b/seed/php-sdk/simple-fhir/src/Types/Script.php
@@ -3,10 +3,13 @@
 namespace Seed\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Traits\BaseResource;
 use Seed\Core\Json\JsonProperty;
 
 class Script extends SerializableType
 {
+    use BaseResource;
+
     /**
      * @var string $resourceType
      */
@@ -23,6 +26,9 @@ class Script extends SerializableType
      * @param array{
      *   resourceType: string,
      *   name: string,
+     *   id: string,
+     *   relatedResources: array<Account|Patient|Practitioner|Script>,
+     *   memo: Memo,
      * } $values
      */
     public function __construct(
@@ -30,5 +36,8 @@ public function __construct(
     ) {
         $this->resourceType = $values['resourceType'];
         $this->name = $values['name'];
+        $this->id = $values['id'];
+        $this->relatedResources = $values['relatedResources'];
+        $this->memo = $values['memo'];
     }
 }
diff --git a/seed/php-sdk/simple-fhir/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/simple-fhir/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/simple-fhir/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/single-url-environment-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/single-url-environment-no-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/streaming-parameter/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/streaming-parameter/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/streaming-parameter/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/streaming/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/streaming/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/streaming/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/trace/src/Playlist/Traits/PlaylistCreateRequest.php b/seed/php-sdk/trace/src/Playlist/Traits/PlaylistCreateRequest.php
new file mode 100644
index 00000000000..3dd5b623fa7
--- /dev/null
+++ b/seed/php-sdk/trace/src/Playlist/Traits/PlaylistCreateRequest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Seed\Playlist\Traits;
+
+use Seed\Core\Json\JsonProperty;
+use Seed\Core\Types\ArrayType;
+
+trait PlaylistCreateRequest
+{
+    /**
+     * @var string $name
+     */
+    #[JsonProperty('name')]
+    public string $name;
+
+    /**
+     * @var array<string> $problems
+     */
+    #[JsonProperty('problems'), ArrayType(['string'])]
+    public array $problems;
+}
diff --git a/seed/php-sdk/trace/src/Playlist/Types/Playlist.php b/seed/php-sdk/trace/src/Playlist/Types/Playlist.php
index 8b16caa92f9..9bcebf5a288 100644
--- a/seed/php-sdk/trace/src/Playlist/Types/Playlist.php
+++ b/seed/php-sdk/trace/src/Playlist/Types/Playlist.php
@@ -3,10 +3,13 @@
 namespace Seed\Playlist\Types;
 
 use Seed\Core\Json\SerializableType;
+use Seed\Playlist\Traits\PlaylistCreateRequest;
 use Seed\Core\Json\JsonProperty;
 
 class Playlist extends SerializableType
 {
+    use PlaylistCreateRequest;
+
     /**
      * @var string $playlistId
      */
@@ -23,6 +26,8 @@ class Playlist extends SerializableType
      * @param array{
      *   playlistId: string,
      *   ownerId: string,
+     *   name: string,
+     *   problems: array<string>,
      * } $values
      */
     public function __construct(
@@ -30,5 +35,7 @@ public function __construct(
     ) {
         $this->playlistId = $values['playlistId'];
         $this->ownerId = $values['ownerId'];
+        $this->name = $values['name'];
+        $this->problems = $values['problems'];
     }
 }
diff --git a/seed/php-sdk/trace/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/trace/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/trace/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/undiscriminated-unions/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/unions/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/unions/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/unions/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/unknown/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/unknown/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/unknown/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/validation/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/validation/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/validation/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/variables/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/variables/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/variables/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/version-no-default/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/version-no-default/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/version-no-default/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/version/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/version/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/version/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}
diff --git a/seed/php-sdk/websocket/tests/Seed/Core/Json/TraitTest.php b/seed/php-sdk/websocket/tests/Seed/Core/Json/TraitTest.php
new file mode 100644
index 00000000000..e23e5c049cc
--- /dev/null
+++ b/seed/php-sdk/websocket/tests/Seed/Core/Json/TraitTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Seed\Tests\Core\Json;
+
+use Seed\Core\Json\SerializableType;
+use Seed\Core\Json\JsonProperty;
+use PHPUnit\Framework\TestCase;
+
+trait IntegerPropertyTrait
+{
+    /**
+     * @var int $integerProperty
+     */
+    #[JsonProperty('integer_property')]
+    public int $integerProperty;
+}
+
+class TypeWithTrait extends SerializableType
+{
+    use IntegerPropertyTrait;
+
+    /**
+     * @var string $stringProperty
+     */
+    #[JsonProperty('string_property')]
+    public string $stringProperty;
+
+    /**
+     * @param array{
+     *   integerProperty: int,
+     *   stringProperty: string,
+     * } $values
+     */
+    public function __construct(array $values)
+    {
+        $this->integerProperty = $values['integerProperty'];
+        $this->stringProperty = $values['stringProperty'];
+    }
+}
+
+class TraitTest extends TestCase
+{
+    public function testTraitPropertyAndString(): void
+    {
+        $data = [
+            'integer_property' => 42,
+            'string_property' => 'Hello, World!',
+        ];
+
+        $json = json_encode($data, JSON_THROW_ON_ERROR);
+
+        $object = TypeWithTrait::fromJson($json);
+
+        $serializedJson = $object->toJson();
+
+        $this->assertJsonStringEqualsJsonString($json, $serializedJson, 'Serialized JSON does not match original JSON for ScalarTypesTestWithTrait.');
+
+        $this->assertEquals(42, $object->integerProperty, 'integer_property should be 42.');
+        $this->assertEquals('Hello, World!', $object->stringProperty, 'string_property should be "Hello, World!".');
+    }
+}