C
Anthropic: claude-sonnet-5-5
claude-sonnet-5-5
1M context128K outReasoningToolsVisionFilesCacheStructuredWeb searchComputer useNative JSON
Released Sep 28, 2026Knowledge cutoff Jan 2026Updated Sep 29, 2026
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing polished documents, slides, and spreadsheets, and it writes and communicates more clearly than its predecessor. Thinking is always on, so effort is the main lever for trading off depth, latency, and cost, and lower effort settings keep it responsive for everyday agentic loops.
Mode chatTokenizer ClaudeReasoning levels maxModerated
Pricing
Input price
$2.10/ 1M tokens
Output price
$10.50/ 1M tokens
Compatible endpoints anthropic, openai, openai-response, openai-response-compact, gemini, openai-alpha-searchVendor Anthropic
Uptime
Performance
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Usage & Ranking
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Supported parameters
All providers = every upstream serving this model supports it. Some providers = depends on which upstream handles the request. Default = the value sent when you leave the parameter unset.
| Parameter | Providers | Default |
|---|---|---|
| include_reasoning | All providers | - |
| max_completion_tokens | Some providers | - |
| max_tokens | All providers | - |
| reasoning | All providers | - |
| reasoning_effort | All providers | - |
| response_format | All providers | - |
| stop | All providers | - |
| structured_outputs | All providers | - |
| temperature | Some providers | - |
| tool_choice | All providers | - |
| tools | All providers | - |
| verbosity | All providers | - |