claude-(Interleaved thinking)

https://platform.claude.com/docs/en/build-with-claude/extended-thinking#interleaved-thinking

To enable interleaved thinking, add the beta header interleaved-thinking-2025-05-14 to your API request.

Here are some important considerations for interleaved thinking:

With interleaved thinking, the budget_tokens can exceed the max_tokens parameter, as it represents the total budget across all thinking blocks within one assistant turn.

Interleaved thinking is only supported for tools used via the Messages API.

Interleaved thinking is supported for Claude 4 models only, with the beta header interleaved-thinking-2025-05-14.

Direct calls to the Claude API allow you to pass interleaved-thinking-2025-05-14 in requests to any model, with no effect.

On 3rd-party platforms (e.g., Amazon Bedrock and Vertex AI), if you pass interleaved-thinking-2025-05-14 to any model aside from Claude Opus 4.5, Claude Opus 4.1, Opus 4, or Sonnet 4, your request will fail.

Request

Authorization

Provide your bearer token in the

Authorization

header when making requests to protected resources.

Example:

Authorization: Bearer ********************

Body Params application/jsonRequired

Example

{
    "model": "claude-opus-4-5-20251101",
    "max_tokens": 2000,
    "messages": [
        {
            "role": "user",
            "content": [
                {
                    "type": "text",
                    "text": "1+2+3+4+...+100=?"
                }
            ]
        }
    ],
    "thinking": {
        "type": "enabled",
        "budget_tokens": 1024
    },
    "temperature": 0.8,
    "steam": false
}

Request Code Samples

Shell

JavaScript

Java

Swift

PHP

Python

HTTP

Objective-C

Ruby

OCaml

Dart

Responses

🟢200OK

application/json

Body

Example

{
    "id": "msg_01RTMUzgfAqheU5zG8vrBwbs",
    "model": "claude-opus-4-5-20251101",
    "object": "chat.completion",
    "created": 1766975951,
    "choices": [
        {
            "index": 0,
            "message": {
                "role": "assistant",
                "content": "# Sum of 1 + 2 + 3 + ... + 100\n\n## Using the formula:\n$$S = \\frac{n(n+1)}{2}$$\n\n## Calculation:\n$$S = \\frac{100 \\times 101}{2} = \\frac{10100}{2} = \\boxed{5050}$$",
                "reasoning_content": "This is asking for the sum of all integers from 1 to 100.\n\nI can use the formula for the sum of an arithmetic series:\nSum = n(n+1)/2\n\nWhere n = 100\n\nSum = 100 × 101 / 2\nSum = 10100 / 2\nSum = 5050",
                "signature": "Eu0CCkYICxgCKkBu42zpywVZcSVzok7y8BF2uUNxH0KfNtSBuLDM/PVbEkegBcoJF5OWv6DC+ksEnUB57x6FZD4BaE3f7TEMdpagEgzBXFDvXgJlbJe3HGwaDIgu4Y6a+3w6craV1SIwtmF/Rurx994wziEq7Hn4RRrJVRh1ZgOoJXfxeT6Jd/UcH4eOKLE/60bDTrDt4ZpgKtQBPOjxRd/bscLm1aDmX4YTr2mZ3bidlJYwB1ktW1GYE4XDeipZ9kP65yZOFqrqcRZwc0bcHh7Wjd8dA9pl0pPu9Oxuijpxwpq4nWfQ5sh6+L2UnULOYgCyTWtUzd0+2AKjs4kFC34Ap1c2eonRjSBxDEcfSRRocZdVQXHAnUEKMrLYOzwl44VPzZSvf3leBIts9LOgQQYDIjEhZI0NTN+ptde7UcKMCMI6jUaKaDbiFCJBpUaCV0avLi3sPkq6/cw6EDSESZ6lARdwi4/o7yeBh8qWhqwYAQ=="
            },
            "finish_reason": "stop"
        }
    ],
    "usage": {
        "prompt_tokens": 50,
        "completion_tokens": 171,
        "total_tokens": 221,
        "prompt_tokens_details": {
            "cached_tokens": 0,
            "text_tokens": 0,
            "audio_tokens": 0,
            "image_tokens": 0
        },
        "completion_tokens_details": {
            "text_tokens": 0,
            "audio_tokens": 0,
            "reasoning_tokens": 0
        },
        "output_tokens_details": {
            "text_tokens": 0,
            "audio_tokens": 0,
            "reasoning_tokens": 0
        },
        "input_tokens": 0,
        "output_tokens": 0,
        "input_tokens_details": null,
        "claude_cache_creation_5_m_tokens": 0,
        "claude_cache_creation_1_h_tokens": 0
    }
}