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Anthropic · Language model
Claude Opus 5.5
anthropic/claude-opus-5.5- Language
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...
Specifications
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Input
- text, image, file
- Output
- text
- Reasoning effort
- max, xhigh, high, medium, low (always on)
- Tokenizer
- Claude
- Moderation
- provider-moderated
Supported parameters
Accepted by the model and forwarded as-is by the gateway.
- max_completion_tokens
- max_tokens
- reasoning
- reasoning_effort
- response_format
- stop
- structured_outputs
- temperature
- tool_choice
- tools
- verbosity
Use it
POST /api/v1/chat/completions · MCP chat · full reference
curl https://omnirail.org/api/v1/chat/completions \
-H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
-d '{"model":"anthropic/claude-opus-5.5","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'