# Claude Opus 5.5

> Anthropic's flagship for long-running agentic coding and knowledge work, succeeding Claude Opus 5. 1M context, 128K output, vision, file input, prompt caching, adaptive thinking.

Human version: https://kymaapi.com/models/claude-opus-5.5
Live JSON: `GET https://kymaapi.com/v1/models` (no auth required)

## Facts

- **Model ID**: `claude-opus-5.5`: pass this as `model` in the request body
- **Creator**: Anthropic
- **Released**: 2026-09-22
- **Context window**: 1M tokens
- **Max output**: 128K tokens per response, a hard ceiling, not a default
- **Price**: $5.40 in / $27.00 out per 1M, cached input $0.27 per 1M
- **Capabilities**: tools, vision, reasoning, caching

## Call it

```bash
curl https://kymaapi.com/v1/chat/completions \
  -H "Authorization: Bearer $KYMA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "claude-opus-5.5", "messages": [{"role": "user", "content": "Hello"}]}'
```

## See also

- All models: https://kymaapi.com/models.md
- Pricing: https://kymaapi.com/pricing.md
- Other models by Anthropic: https://kymaapi.com/models?q=Anthropic