Skip to main content

'Thinking' / 'Reasoning Content'

Supported Providers:

  • Deepseek (deepseek/)
  • Anthropic API (anthropic/)
  • Bedrock (Anthropic + Deepseek) (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": "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
}

Tool Calling with thinking​

Here's how to use thinking blocks by Anthropic with tool calling.

litellm._turn_on_debug()
litellm.modify_params = True
model = "anthropic/claude-3-7-sonnet-20250219" # works across Anthropic, Bedrock, Vertex AI
# Step 1: send the conversation and available functions to the model
messages = [
    {
        "role": "user",
        "content": "What's the weather like in San Francisco, Tokyo, and Paris? - give me 3 responses",
    }
]
tools = [
    {
        "type": "function",
        "function": {
            "name": "get_current_weather",
            "description": "Get the current weather in a given location",
            "parameters": {
                "type": "object",
                "properties": {
                    "location": {
                        "type": "string",
                        "description": "The city and state",
                    },
                    "unit": {
                        "type": "string",
                        "enum": ["celsius", "fahrenheit"],
                    },
                },
                "required": ["location"],
            },
        },
    }
]
response = litellm.completion(
    model=model,
    messages=messages,
    tools=tools,
    tool_choice="auto",  # auto is default, but we'll be explicit
    thinking={"type": "enabled", "budget_tokens": 1024},
)
print("Response\n", response)
response_message = response.choices[0].message
tool_calls = response_message.tool_calls

print("Expecting there to be 3 tool calls")
assert (
    len(tool_calls) > 0
)  # this has to call the function for SF, Tokyo and paris

# Step 2: check if the model wanted to call a function
print(f"tool_calls: {tool_calls}")
if tool_calls:
    # Step 3: call the function
    # Note: the JSON response may not always be valid; be sure to handle errors
    available_functions = {
        "get_current_weather": get_current_weather,
    }  # only one function in this example, but you can have multiple
    messages.append(
        response_message
    )  # extend conversation with assistant's reply
    print("Response message\n", response_message)
    # Step 4: send the info for each function call and function response to the model
    for tool_call in tool_calls:
        function_name = tool_call.function.name
        if function_name not in available_functions:
            # the model called a function that does not exist in available_functions - don't try calling anything
            return
        function_to_call = available_functions[function_name]
        function_args = json.loads(tool_call.function.arguments)
        function_response = function_to_call(
            location=function_args.get("location"),
            unit=function_args.get("unit"),
        )
        messages.append(
            {
                "tool_call_id": tool_call.id,
                "role": "tool",
                "name": function_name,
                "content": function_response,
            }
        )  # extend conversation with function response
    print(f"messages: {messages}")
    second_response = litellm.completion(
        model=model,
        messages=messages,
        seed=22,
        # tools=tools,
        drop_params=True,
        thinking={"type": "enabled", "budget_tokens": 1024},
    )  # get a new response from the model where it can see the function response
    print("second response\n", second_response)

Switching between Anthropic + Deepseek models​

Set drop_params=True to drop the 'thinking' blocks when swapping from Anthropic to Deepseek models. Suggest improvements to this approach here.

litellm.drop_params = True # 👈 EITHER GLOBALLY or per request

# or per request
## Anthropic
response = litellm.completion(
  model="anthropic/claude-3-7-sonnet-20250219",
  messages=[{"role": "user", "content": "What is the capital of France?"}],
  thinking={"type": "enabled", "budget_tokens": 1024},
  drop_params=True,
)

## Deepseek
response = litellm.completion(
  model="deepseek/deepseek-chat",
  messages=[{"role": "user", "content": "What is the capital of France?"}],
  thinking={"type": "enabled", "budget_tokens": 1024},
  drop_params=True,
)

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 - str: The signature delta from the model.