Claude Opus 5.5
Language modelCard summarizedFor long-running agentic coding and knowledge work
Overview
Anthropic · 03Opus, front
Opus 5.5
For long-running agentic coding and knowledge work
- Cost
- $4.00 in
- Context
- 1M
- Input / output
- $4.00 / $20.00
- Max output
- 128K
- Knows up to
- June 2026
- Released
- 22 Sep 2026
Anthropic's latest Opus-class large language model. It upgrades Claude Opus 5 with gains in coding, agentic and computer-use tasks, mathematical and scientific reasoning, and long-horizon professional work, and on many evaluations it matches or exceeds Claude Fable 5.1. p.2
claude-opus-5-5- Input / output per 1M
- $4.00 / $20.00
- Context window
- 1M
- Max output
- 128K
- Knows up to
- June 2026
- Reasoning
- Adaptive (always on)
- Weights
- Closed
About this card. A model card is the maker's own account of a model: what it's for, how it was trained and tested, and where it falls short. This page condenses Anthropic's System Card: Claude Opus 5.5. Every claim carries its source page.