Simulate tool calls via messages in generateText()

[humphd]

I love the built-in tool calling in the AI SDK, it works great; however, I currently need to be able to handle tool calls on my own, and pass through the raw tool_calls and tool messages to the chat completion, having generateText() leave them alone. Essentially, I need to know how to format my tool call(s) and result(s) in a format that will mimic what generateText() does internally with multi-step calling.

If I was doing a raw chat completion with OpenAI, I'd structure my tool call/result like this:

// The LLM indicating a tool call
{
    role: "assistant",
    tool_calls: [
        {
            id: "call_edh9uihrtvsUUIQKpi2K2m4P",
            type: "function",
            function: {
                name: "getCurrentTemperature",
                arguments: '{"unit":"Fahrenheit","location":"San Francisco, CA"}',
            },
        },
    ],
},

// The result of the tool call
{
    role: "tool",
    tool_call_id: "call_edh9uihrtvsUUIQKpi2K2m4P",
    content: "57",
},

However, adding such messages to generateText() produces type errors:

Type '{ role: "assistant"; tool_calls: { id: string; type: string; function: { name: string; arguments: string; }; }[]; }' is not assignable to type 'UIMessage'.
Object literal may only specify known properties, and 'tool_calls' does not exist in type 'UIMessage'.

Type '"tool"' is not assignable to type '"system" | "user" | "assistant" | "data"'.ts(2322)
index.d.ts(750, 5): The expected type comes from property 'role' which is declared here on type 'UIMessage'

How should I be formatting them so that the completed call + result messages are part of what the LLM receives?

[humphd]

I solved this by implementing something similar to what's done in convertToCoreMessages(), such that my two messages look like this:

    {
      role: 'assistant',
      content: [
        {
          type: 'tool-call',
          toolCallId: 'call_as7qQ0YoKn1Si5nrZQoyMPS6',
          toolName: 'getCurrentTemperature',
          args: '{"unit":"Fahrenheit","location":"San Francisco, CA"}'
        }
      ]
    },
    {
      role: 'tool',
      content: [
        {
          type: 'tool-result',
          toolCallId: 'call_as7qQ0YoKn1Si5nrZQoyMPS6',
          toolName: 'getCurrentTemperature',
          result: '57'
        }
      ]
    }