Support Gemini thought_signature from extra_content in tool calls (generic-chat-completion-api)

[agamble-quora]

This request is to support thinking Gemini models (e.g. Gemini-3-Pro) using tools over chat completions endpoint and generic-chat-completion-api provider.

thought_signature is required for tool calls: https://ai.google.dev/gemini-api/docs/thought-signatures#openai

e.g:

{
      "role": "model",
        "tool_calls": [
          {
            "extra_content": {
              "google": {
                "thought_signature": "<Signature A>"
              }
            },
            "function": {
              "arguments": "{\"flight\":\"AA100\"}",
              "name": "check_flight"
            },
            "id": "function-call-1",
            "type": "function"
          }
        ]
    }

The generic-chat-completion-api provider needs to be updated to retain the extra_content field to be passed back to the model with the tool call result.

Thanks!

[Ricardo-DEPT]

+1, can't use gemini 3 now