Model detail
Claude Opus 4.5 20251101
Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use. It offers strong multimodal capabilities, competitive performance across real-world coding and reasoning benchmarks, and improved robustness to prompt injection. The model is designed to operate efficiently across varied effort levels, enabling developers to trade off speed, depth, and token usage depending on task requirements. It comes with a new parameter to control token efficiency, which can be accessed using the OpenRouter Verbosity parameter with low, medium, or high. Opus 4.5 supports advanced tool use, extended context management, and coordinated multi-agent setups, making it well-suited for autonomous research, debugging, multi-step planning, and spreadsheet/browser manipulation. It delivers substantial gains in structured reasoning, execution reliability, and alignment compared to prior Opus generations, while reducing token overhead and improving performance on long-running tasks.
Model specs
- Model ID
-
claude-opus-4-5-20251101
- Context length
- 200K
- Max output
- 64K
- I/O modalities
- Released
- 2025-11
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API endpoints
One MixRoute gateway, OpenAI-compatible
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Anthropic Messages
/v1/messagesPOST -
OpenAI-compatible
/v1/chat/completionsPOST -
Gemini
/v1beta/models/{model}:generateContentPOST
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Pricing
Flat rate, unit: /1M Tokens
Input
$5.0000 /1M Tokens
Completion
$25.0000 /1M Tokens
Cache read
$0.5000 /1M Tokens
Cache creation
$6.2500 /1M Tokens
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Selection summary
Quickly judge whether it fits your workload
What is this model good for?
Complex software engineering and multi-agent setups
Use Claude Opus 4.5 for autonomous research, debugging, multi-step planning, and spreadsheet/browser manipulation. It supports advanced tool use, extended context management, and coordinated multi-agent setups.
What should you check before using it?
Tune token efficiency and tool orchestration
Opus 4.5 supports a verbosity parameter (low/medium/high) to control token efficiency. Test your multi-agent setups and verify the improved prompt injection robustness. Knowledge cutoff: 2025-05.
Why use it through MixRoute?
Claude Opus 4.5 cache reads cut repeated-prompt cost
Cached prefixes are billed at 0.50 USD per 1M tokens instead of 5 USD, so repeated system prompts cost less. MixRoute serves Claude Opus 4.5 on the OpenAI-compatible endpoint /v1/chat/completions; point your existing client at https://api.mixroute.ai/v1 with the model ID claude-opus-4-5-20251101 and re-run your integration tests.
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Capabilities & compatibility
Unconfirmed capabilities stay "Unknown," no guesses
Tool calling
Claude Opus 4.5 supports function and tool calls.
tools definition; the response returns tool_calls to execute and feed results back.
Structured output
Claude Opus 4.5 can produce JSON-formatted output on demand.
response_format: { type: "json_schema" } forces valid JSON output.
Streaming
Claude Opus 4.5 supports streamed responses.
stream: true streams tokens incrementally, so chat UIs render as they arrive.
Prompt caching
Claude Opus 4.5 supports prompt caching under supported routing conditions.
Vision input
Claude Opus 4.5 can process image inputs alongside text.
image_url content part alongside text messages.
OpenAI SDK
Call Claude Opus 4.5 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
Compare claude-opus-4-5-20251101 against models of similar capability and pricing on your actual workload. Evaluate latency, output quality, instruction following, and cost per task. Run side-by-side tests with your own prompts — the best model depends on your specific use case, not just benchmark scores.
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.