Claude Opus 5.5
Claude Opus 5.5 by Anthropic: frontier foundation model performing at Claude Fable 5.1 level, featuring a 1M context and agentic coding capabilities.
Model Overview
Capabilities, design details, and architectural traits
Claude Opus 5.5 - Frontier Model for Complex Agentic Coding and Knowledge Work
Claude Opus 5.5 is Anthropic's frontier model in the Claude 5.5 generation. It delivers intelligence on par with Claude Fable 5.1 across most workloads, with output token generation speed increased by over 30%.
| Trait | Detail |
|---|---|
| Context Window | 1,000,000 tokens (1M tokens) native capacity |
| Safety & Verification | Integrates Cyber and Life Sciences verification safeguards |
Frontier Performance & Real-World Agentic Engineering
Opus 5.5 introduces major architectural refinements in multi-hour autonomous execution, software refactoring, and code migration. In real-world enterprise evaluations, it completed a 680,000-line code migration in less than a day. It communicates with clearer, more natural phrasing and supports adaptive thinking up to maximum effort for complex multidisciplinary challenges.
Benchmark Performance
Independent evaluations · Artificial Analysis
Accuracy & Capability Details
Compare Models Side-by-Side
Evaluate specifications, pricing, and independent benchmark indices
| Model Details | |||
|---|---|---|---|
| General Info | |||
| Provider | Anthropic | Anthropic | |
| Release Date | September 22, 2026 | November 9, 2026 | October 28, 2026 |
| Knowledge Cutoff | - | - | - |
| Context & Limits | |||
| Context Window | 1M | 1M | 1.0M Best Context Window |
| Pricing (per 1M tokens) | |||
| Input Pricing | $4 | $8 | $2 Best Input Pricing |
| Output Pricing | $20 | $40 | $10 Best Output Pricing |
| Modalities | |||
| Inputs | textimagefile | textimagefile | text |
| Outputs | text | text | text |
| Benchmarks (0-100) | |||
| Intelligence Index | 59.1 | 64.6 Best Intelligence Index | 60.0 |
| Coding Index | - | - | - |
| Agentic Index | - | - | - |
Humanity's Last Exam
Extremely difficult logical reasoning and knowledge.
Long Context Reasoning
Logical reasoning over long context windows.
SciCode Benchmark
Scientific coding and mathematical modeling.
Independent evaluation data provided by Artificial Analysis. To view the latest benchmarks and full details, visit their official site.
Explore more from Anthropic
Other models by Anthropic
Claude Fable 5.2
Claude Sonnet 5.5
Claude Fable 5
Claude Fable 5.1
Top AI Models
Leading alternatives by intelligence score
