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Anthropic: claude-sonnet-5-5

claude-sonnet-5-5
1M context128K outReasoningToolsVisionFilesCacheStructuredWeb searchComputer useNative JSON
Released Sep 28, 2026Knowledge cutoff Jan 2026Updated Oct 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

Inputs used for the providers' own purposes

At least one provider of this model uses your inputs for its own purposes, for example to train AI models. Do not enter personal data of third parties or sensitive data. You can object to this use at any time in your account settings or via "Manage consents" in the chat.

Read the privacy policy

Pricing

Input price
$0.45/ 1M tokens78% off
Output price
$2.23/ 1M tokens78% off
Compatible endpoints openaiVendor AnthropicProvider Routerah

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.

ParameterProvidersDefault
include_reasoningAll providers-
max_completion_tokensSome providers-
max_tokensAll providers-
reasoningAll providers-
reasoning_effortAll providers-
response_formatAll providers-
stopAll providers-
structured_outputsAll providers-
tool_choiceAll providers-
toolsAll providers-
verbosityAll providers-

Frequently asked questions

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