Claude Sonnet 5.5
Claude Sonnet 5.5 targets everyday coding, writing and agent work. Existing applications need to check their request options: familiar sampling settings are not accepted by this model.
The lowest thinking mode still has a specific purpose
Adaptive thinking is enabled by default. The between_tools setting removes up-front thinking and works at high effort or below. It should not be treated as the same control as temperature.Claude Sonnet 5.5 reference
Review the request builder as well as the prompt
Practical guidance. When migrating an application, inspect shared request defaults. An unused temperature field can still cause an invalid request. Keep model-specific capability checks close to the code that builds the request.Claude Sonnet 5.5 reference
Use a revision task with observable requirements
Practical guidance. For a product description, provide the product facts, intended reader and statements that need evidence. Ask for a revision that preserves those facts. Judge whether the result answers the reader’s question, rather than whether it sounds polished.
Specifications & access
| Detail | Value and conditions |
|---|---|
| Launch date | |
| Access | API |
| Model identifiers | claude-sonnet-5-5 |
| Context window | 1,000,000 tokens Context limit Claude Sonnet 5.5 reference |
| Maximum output | 128,000 tokens Ordinary maximum output Claude Sonnet 5.5 reference |
| Input price | 2 USD per million tokens Standard input rate Claude Sonnet 5.5 reference |
| Output price | 10 USD per million tokens Standard output rate Claude Sonnet 5.5 reference |
| Unsupported parameters | temperature, top_p and top_k return a 400 error.Claude Sonnet 5.5 reference |
| Default effort | highClaude Sonnet 5.5 reference |
| Minimum cacheable prompt | 512 tokensClaude Sonnet 5.5 reference |
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