Log thinking blocks

How to log LLM requests that include thinking blocks

When using models with thinking capabilities, the response includes additional reasoning information that can be logged and analyzed.

Response Structure

Thinking-enabled responses include these additional fields:

• reasoning_content: The model’s reasoning process in text format
• thinking_blocks: Array of structured thinking blocks with signatures

Example Request

{
  "model": "claude-sonnet-4-20250514",
  "max_tokens": 16000,
  "thinking": {
    "type": "enabled",
    "budget_tokens": 10000
  },
  "messages": [
    {
      "role": "user",
      "content": "Are there an infinite number of prime numbers such that n mod 4 == 3?"
    }
  ]
}

Example Response

{
  "messages": [
    {
      "role": "user",
      "content": "Are there an infinite number of prime numbers such that n mod 4 == 3?"
    },
    {
      "role": "assistant",
      "content": "Yes, there are infinitely many prime numbers such that n ≡ 3 (mod 4).\n\nThis is a classic theorem in number theory, and here's a proof…",
      "reasoning_content": "This is asking about whether there are infinitely many prime numbers that are congruent to 3 modulo 4, i.e., primes of the form 4k + 3.\n\nLet me think about this systematically. First…",
      "thinking_blocks": [
        {
          "type": "thinking",
          "thinking": "This is asking about whether there are infinitely many prime numbers that are congruent to 3 modulo 4, i.e…",
          "signature": "EswgCkYIBhgCKkDCG…"
        }
      ],
      "tool_calls": []
    }
  ]
}

Logging Parameters

All standard logging parameters apply. The thinking-related fields are automatically captured when present:

• reasoning_content: Full reasoning text
• thinking_blocks: Array of thinking block objects
• signature: Cryptographic signature for thinking block verification

Key Points

• Thinking blocks are automatically logged when present in the response
• The reasoning_content field contains the complete reasoning process
• thinking_blocks provide structured access to individual reasoning steps
• All other logging parameters work the same as regular text logging

For more information on enabling thinking mode, see the Enable Thinking documentation.