diff --git a/cairo/crates/contracts/src/hooks/libs/standard_hook_metadata.cairo b/cairo/crates/contracts/src/hooks/libs/standard_hook_metadata.cairo
index 1973471b..ca9c9bc6 100644
--- a/cairo/crates/contracts/src/hooks/libs/standard_hook_metadata.cairo
+++ b/cairo/crates/contracts/src/hooks/libs/standard_hook_metadata.cairo
@@ -23,7 +23,7 @@ pub mod standard_hook_metadata {
     const GAS_LIMIT_OFFSET: u8 = 34;
     const REFUND_ADDRESS_OFFSET: u8 = 66;
     const MIN_METADATA_LENGTH: u256 = 98;
-
+    const U128_NUMBER_OF_BYTES: usize = 16;
     pub const VARIANT: u8 = 1;
 
     #[generate_trait]
@@ -140,7 +140,7 @@ pub mod standard_hook_metadata {
                 refund_address_u256.high
             ];
 
-            let mut formatted_metadata = BytesTrait::new(data.len(), data);
+            let mut formatted_metadata = BytesTrait::new(data.len() * U128_NUMBER_OF_BYTES, data);
             formatted_metadata.concat(@custom_metadata);
             formatted_metadata
         }
diff --git a/cairo/crates/contracts/src/mailbox.cairo b/cairo/crates/contracts/src/mailbox.cairo
index bef7c65b..b2ef08f4 100644
--- a/cairo/crates/contracts/src/mailbox.cairo
+++ b/cairo/crates/contracts/src/mailbox.cairo
@@ -255,7 +255,7 @@ pub mod mailbox {
                 Option::Some(hook_metadata) => {
                     let mut sanitized_bytes_metadata = BytesTrait::new_empty();
                     sanitized_bytes_metadata.concat(@hook_metadata);
-                    assert( // what does this exactly checks
+                    assert(
                         sanitized_bytes_metadata == hook_metadata,
                         Errors::SIZE_DOES_NOT_MATCH_METADATA
                     );