added

Reasoning field now included in the API response

With the latest update to our reasoning models, API responses now include the reasoning and reasoning_signature fields. These additions provide more transparency into how the model arrives at its answers.

See an example below:

{
    "id": "01JWQZ1JB6PSJ1F8KSWE5771GR",
    "created": "2025-06-02T09:19:59.308Z",
    "object": "vision",
    "model": "claude-sonnet-4-20250514",
    "provider": "anthropic",
    "is_final": true,
    "finalized": "2025-06-02T09:20:05.615Z",
    "choices": [
        {
            "index": 0,
            "message": {
                "role": "assistant",
                "content": "",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "toolu_01A57N7TgYAqcFmiMY9Q7TT4",
                        "index": 0,
                        "function": {
                            "name": "AA_tool",
                            "arguments": "{\"question\":\"How large can my carry on bag be?\",\"answer\":\"Your carry-on bag must not exceed 22 x 14 x 9 inches (56 x 36 x 23 cm), including handles and wheels. There is no weight limit for carry-on bags, but you must be able to lift it into the overhead bin without assistance.\"}"
                        }
                    }
                ],
                "reasoning": "The user is asking about carry-on bag size limits for American Airlines. Let me check the knowledge base for relevant information.\n\nLooking at the knowledge base, I can see there's a question that directly addresses this: \"What are the size and weight limits for carry-on bags?\" with the answer: \"Your carry-on bag must not exceed 22 x 14 x 9 inches (56 x 36 x 23 cm), including handles and wheels. There is no weight limit for carry-on bags, but you must be able to lift it into the overhead bin without assistance.\"\n\nThis question is clearly related to American Airlines travel and I have the relevant information in the knowledge base to answer it. I should use the AA_tool to structure my response.",
                "reasoning_signature": "Euxxx",
                "type": "tool_calls"
            },
            "finish_reason": "tool_use"
        }
    ],
    "provider_response": {
        "id": "msg_01VDbNW9N2khGgx16x5texpt",
        "type": "message",
        "role": "assistant",
        "model": "claude-sonnet-4-20250514",
        "content": [
            {
                "type": "thinking",
                "thinking": "The user is asking about carry-on bag size limits for American Airlines. Let me check the knowledge base for relevant information.\n\nLooking at the knowledge base, I can see there's a question that directly addresses this: \"What are the size and weight limits for carry-on bags?\" with the answer: \"Your carry-on bag must not exceed 22 x 14 x 9 inches (56 x 36 x 23 cm), including handles and wheels. There is no weight limit for carry-on bags, but you must be able to lift it into the overhead bin without assistance.\"\n\nThis question is clearly related to American Airlines travel and I have the relevant information in the knowledge base to answer it. I should use the AA_tool to structure my response.",
                "signature": "Euxxx"
            },
            {
                "type": "tool_use",
                "id": "toolu_01A57N7TgYAqcFmiMY9Q7TT4",
                "name": "AA_tool",
                "input": {
                    "question": "How large can my carry on bag be?",
                    "answer": "Your carry-on bag must not exceed 22 x 14 x 9 inches (56 x 36 x 23 cm), including handles and wheels. There is no weight limit for carry-on bags, but you must be able to lift it into the overhead bin without assistance."
                }
            }
        ],
        "stop_reason": "tool_use",
        "stop_sequence": null,
        "usage": {
            "input_tokens": 984,
            "cache_creation_input_tokens": 0,
            "cache_read_input_tokens": 0,
            "output_tokens": 312,
            "service_tier": "standard"
        }
    }
}