Model detail
Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code review and bug finding, financial and scientific analysis, and reading dense charts, diagrams, and screenshots, and it is more careful than its predecessor about only stating figures and citing sources it can back up. The model completes comparable tasks in fewer steps and with fewer tokens than Opus 5, and reports on its work in plainer language, with clear updates on what it did, what it found, and what it needs from the user. Thinking is always adaptive, so effort is the main lever for trading off depth, latency, and cost, and lower effort settings remain effective for latency-sensitive workloads.
Model specs
- Model ID
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claude-opus-5-5
- Context length
- 1M
- Max output
- 128K
- I/O modalities
- Released
- 2026-09
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API endpoints
One MixRoute gateway, OpenAI-compatible
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Anthropic Messages
/v1/messagesPOST -
OpenAI-compatible
/v1/chat/completionsPOST
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Pricing
Flat rate, unit: /1M Tokens
Input
$4.0000 /1M Tokens
Completion
$20.0000 /1M Tokens
Cache read
$0.2000 /1M Tokens
Cache creation
$5.0000 /1M Tokens
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Selection summary
Quickly judge whether it fits your workload
What is this model good for?
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
What should you check before using it?
1,000,000 context, 128,000 output tokens
claude-opus-5-5 supports reasoning, tool calling, structured output, streaming, prompt caching, vision input and the OpenAI SDK. Knowledge cutoff: 2026-06. Released 2026-09-22.
Why use it through MixRoute?
claude-opus-5-5 cache reads cut repeated-prompt cost
Cached prefixes are billed at 0.20 USD per 1M tokens instead of 4 USD, so repeated system prompts cost less. MixRoute serves claude-opus-5-5 on the OpenAI-compatible endpoint /v1/chat/completions; point your existing client at https://api.mixroute.ai/v1 with the model ID claude-opus-5-5 and re-run your integration tests.
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Capabilities & compatibility
Unconfirmed capabilities stay "Unknown," no guesses
Tool calling
claude-opus-5-5 supports function and tool calls.
tools definition; the response returns tool_calls to execute and feed results back.
Structured output
claude-opus-5-5 can produce JSON-formatted output on demand.
response_format: { type: "json_schema" } forces valid JSON output.
Streaming
claude-opus-5-5 supports streamed responses.
stream: true streams tokens incrementally, so chat UIs render as they arrive.
Prompt caching
claude-opus-5-5 supports prompt caching under supported routing conditions.
Vision input
claude-opus-5-5 can process image inputs alongside text.
image_url content part alongside text messages.
OpenAI SDK
Call claude-opus-5-5 through MixRoute's OpenAI-compatible endpoint.
base_url to https://api.mixroute.ai/v1; everything else follows the OpenAI style.
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Token cost estimator
Live estimate from this page's pricing, not an actual bill
Share of the same prefix read repeatedly, up to 100%
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FAQ
Recorded results for claude-opus-5-5: aa_intelligence_index 100.0; arena_text 100.0. Benchmark positions are a coarse filter only — run your own prompts against the candidate models before you commit, because ranking shifts with task shape and prompt style.
One endpoint, a testable decision
Test this model and alternate routes with the same request format
Start from a real workload, then let quality, total cost, and failure conditions decide whether to send production traffic.