Anthropic/claude-opus-4-5-20251101/Released Nov 2025

Claude Opus 4.5

Software engineering and agentic workflows

Commercial use
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About Claude Opus 4.5

Claude Opus 4.5 is an LLM designed for complex specialized tasks, professional software engineering, and advanced agentic workflows.

It excels in long-horizon reasoning, robust context management across extended multi-turn interactions, and advanced coding capabilities. Notably, Claude Opus 4.5 introduces an effort parameter, allowing users to control the depth and thoroughness of responses, enabling dynamic trade-offs between token efficiency and reasoning quality within the same model.

Some other noteworthy features of Claude Opus 4.5 include support for advanced tool use, coordinated multi-agent setups, and strong multimodal capabilities, making it especially suitable for autonomous research, debugging, multi-step planning, and spreadsheet/browser manipulation.

MetricValue
Context Length200,000 tokens
MultilingualYes

Ready to build with Claude Opus 4.5?

Try Claude Opus 4.5 in the Workbench to prompt it, compare outputs, and iterate on prompts without writing any code. When you're ready to ship, call the same model from our API and build your own apps on top of it.

curl -sSf -X POST https://hub.oxen.ai/api/ai/chat/completions \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer $OXEN_API_KEY" \
    -d '{
  "model": "claude-opus-4-5-20251101",
  "messages": [
    {
      "role": "user",
      "content": "Try sending a message."
    }
  ]
}'

API endpoint

See the API reference for request and response formats.

POSThttps://hub.oxen.ai/api/ai/chat/completions