Claude Opus 5.5
A deep-reasoning and agentic-coding specialist that trades a little of Fable's polish for a stronger price-to-capability ratio. The go-to Claude model for engineering teams running autonomous coding agents.
At a glance
Released
Sep 15, 2026
Provider
Anthropic
Context window
1,000,000 tokens
Max output
128,000 tokens
Modalities
Text + image → text
Knowledge cutoff
June 2026
API model ID
claude-opus-5-5License
Proprietary (API only)
Pricing
Standard
Input$4 / 1M
Output$20 / 1M
Batch (50% off)
Input$2 / 1M
Output$10 / 1M
A typical 1,500-token prompt with a 650-token answer costs ≈ $0.019 on the standard tier. Run your own prompt through the calculator →
What's new vs the previous model
Compared withClaude Opus 5 (April 2026)
- Better sustained performance on long agentic coding tasks
- Improved step-by-step reasoning and self-correction
- More efficient token use on extended runs
- Still pricier than the Sonnet workhorse tier
Best use cases
Agentic coding
Plans and edits across large codebases with many tool calls.
Complex reasoning
Works through multi-step technical and analytical problems.
Research assistance
Synthesizes long documents into structured conclusions.
Strengths & limitations
Strengths
- Strong agentic coding
- Deep reasoning
- Good cost-to-capability
- Reliable long runs
Limitations
- Costlier than balanced tiers
- Overkill for simple tasks
How to test it
- No-code: open claude.ai and pick Claude Opus 5.5 from the model switcher — no API key needed.
- Playground: sign in to the Anthropic Console and run prompts in the workbench, then copy the generated code.
- API: create a key in the Anthropic Console and call the API (example below).
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-opus-5-5",
"max_tokens": 1024,
"messages": [{"role": "user", "content": "Explain tokenization in one paragraph."}]
}'Where to get access
Consumer app
Chat with Claude Opus 5.5 in Claude apps (web, macOS, Windows, iOS, Android).
claude.ai ↗