Anthropic: Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code... Flagship reasoning and coding capability 1M-token context window Strong long-horizon agent positioning High output-token price Limited independent evaluation data Large codebase changes Complex research Long-running agents
Specifications
| Lab | Anthropic |
|---|---|
| Context window | 1,000,000 |
| Input price | $4.00/1M |
| Output price | $20.00/1M |
| Release | 2026-09-01 00:00:00 |
Strengths
- Flagship reasoning and coding capability
- 1M-token context window
- Strong long-horizon agent positioning
Weaknesses
- High output-token price
- Limited independent evaluation data
Best for
- Large codebase changes
- Complex research
- Long-running agents
In Depth: Claude Opus 5.5
Summary
Claude Opus 5.5 is an AI model from Anthropic.
Released 2026-09-01 00:00:00. It supports Text, image, file input and produces Text output, with a context window of 1M tokens. Input pricing is $4.00 per 1M tokens and output is $20.00 per 1M tokens on OpenRouter.