Claude Opus 5.5
claude-opus-5-5
Anthropic · reasoning · api
Intelligence
Context
1M
Max output
128K
Input $/1M
$4.00
Output $/1M
$20.00
Modalities
text · image · document
Released
21 Sept 2026
Intelligence Index via Artificial Analysis · 0–100, higher is better
AI summary
● machine-written
Claude Opus 5.5: Anthropic's mid-tier reasoning model
Claude Opus 5.5 is Anthropic's general-purpose model positioned between Sonnet 5 and Fable 5.1, designed for long-running agentic coding and knowledge work. It supports text, image, and document input with a 1M token context window and 128K token max output. The model features adaptive thinking and is available via API in general availability status.
What's new
- Pricing at $4 input / $20 output per million tokens
- Prompt caching with $0.20 per million tokens for cache hits (5% of base input rate)
- 1M context window with 128K max output
- Adaptive thinking enabled by default
Best for
Long-running agentic coding tasksKnowledge work and information synthesisApplications requiring extended context processingCost-sensitive deployments vs. Fable 5.1
Common questions about Claude Opus →
Source: https://docs.claude.com/en/docs/about-claude/models/overview