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'Thinking' / 'Reasoning Content'

Supported Providers:

  • Deepseek (deepseek/)
  • Anthropic API (anthropic/)
  • Bedrock (Anthropic) (bedrock/)
  • Vertex AI (Anthropic) (vertexai/)
"message": {
    ...
    "reasoning_content": "The capital of France is Paris.",
    "thinking_blocks": [
        {
            "type": "thinking",
            "thinking": "The capital of France is Paris.",
            "signature_delta": "EqoBCkgIARABGAIiQL2UoU0b1OHYi+..."
        }
    ]
}

Quick Start​

from litellm import completion
import os 

os.environ["ANTHROPIC_API_KEY"] = ""

response = completion(
  model="anthropic/claude-3-7-sonnet-20250219",
  messages=[
    {"role": "user", "content": "What is the capital of France?"},
  ],
  thinking={"type": "enabled", "budget_tokens": 1024} # 👈 REQUIRED FOR ANTHROPIC models (on `anthropic/`, `bedrock/`, `vertexai/`)
)
print(response.choices[0].message.content)

Expected Response

{
    "id": "3b66124d79a708e10c603496b363574c",
    "choices": [
        {
            "finish_reason": "stop",
            "index": 0,
            "message": {
                "content": " won the FIFA World Cup in 2022.",
                "role": "assistant",
                "tool_calls": null,
                "function_call": null
            }
        }
    ],
    "created": 1723323084,
    "model": "deepseek/deepseek-chat",
    "object": "chat.completion",
    "system_fingerprint": "fp_7e0991cad4",
    "usage": {
        "completion_tokens": 12,
        "prompt_tokens": 16,
        "total_tokens": 28,
    },
    "service_tier": null
}

Spec​

These fields can be accessed via response.choices[0].message.reasoning_content and response.choices[0].message.thinking_blocks.

  • reasoning_content - str: The reasoning content from the model. Returned across all providers.
  • thinking_blocks - Optional[List[Dict[str, str]]]: A list of thinking blocks from the model. Only returned for Anthropic models.
    • type - str: The type of thinking block.
    • thinking - str: The thinking from the model.
    • signature_delta - str: The signature delta from the model.