Claude Sonnet 5.5
Best speed/intelligence balance. Adaptive thinking on by default (effort default high); thinking {type: disabled} returns 400, use {type: between_tools} at effort high or below; forced tool_choice any/tool returns 400; non-default temperature/top_p/top_k return 400. Batch $1/$5.
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Knowledge cutoff
- 2026-06
- Input
- text, image, pdf
- Output
- text
- License
- proprietary
- Pricing
- input: $2 · output: $10 · cache read: $0.2 (per 1M tokens (USD); Batch API 50% off) source
- Verified
- 2026-09-29
How to call it
| Provider | Model id | Endpoint / URL | Docs |
|---|---|---|---|
| Anthropic API (Claude API) | claude-sonnet-5-5 | https://api.anthropic.com/v1/messages | docs |
| AWS Bedrock (Messages API / Mantle) | anthropic.claude-sonnet-5-5 | — | docs |
| Google Cloud Vertex AI | claude-sonnet-5-5 | — | docs |
| Microsoft Foundry (Azure) | claude-sonnet-5-5 | — | docs |
| Claude Platform on AWS | claude-sonnet-5-5 | — | docs |
| OpenRouter | anthropic/claude-sonnet-5.5 | openrouter.ai/anthropic/claude-sonnet-5.5 | — |
| Web app | — | claude.ai | — |
Notable capabilities (5)
- Opus-level knowledge work at Sonnet price: Scores nearly level with Opus 5.5 on GDPval-AA (1844 vs 1846 Elo), at $2/$10 per MTok. source
- Large agentic-coding jump: Anthropic reports 70.6% on Terminal-Bench 4.0, up from 10.3% for Sonnet 5, and up to 30% lower cost per task. source
- FIRST Beat Pokemon Red from screenshots: Anthropic says it is the first Sonnet model to finish Pokemon Red using only screenshots. source
- FIRST between_tools thinking mode: New thinking type that turns off up-front thinking while still reasoning between tool calls; it replaces thinking: disabled. source
- Token efficiency: A Balyasny test used 121k tokens per task, versus 497k for Sonnet 5. source
Everyday coding, agents and enterprise workloads at Sonnet pricing; successor to Claude Sonnet 5 at the same price.
curl https://api.anthropic.com/v1/messages \
-H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" -H "content-type: application/json" \
-d '{"model":"claude-sonnet-5-5","max_tokens":16000,"messages":[{"role":"user","content":"Hello"}]}'
Sources:
- Model page: https://platform.claude.com/docs/en/models/sonnet-5-5/overview
- Announcement: https://www.anthropic.com/claude-sonnet-5-5
- Pricing: https://platform.claude.com/docs/en/about-claude/pricing
- Models overview: https://platform.claude.com/docs/en/about-claude/models/overview
- Deprecations: https://platform.claude.com/docs/en/about-claude/model-deprecations
Other Anthropic models
Claude Opus 5.5 · Claude Fable 5.1 · Claude Mythos 5.1 · Claude Haiku 4.5 · Claude Opus 5 · Claude Sonnet 5 · Claude Fable 5 · Claude Opus 4.8 · Claude Opus 4.7 · Claude Sonnet 4.6 · Claude Opus 4.6 · Claude Opus 4.5 · Claude Sonnet 4.5 · Claude Opus 4.1 · Claude Sonnet 4