Claude Opus 4.1
Claude Opus 4.1 by Anthropic is a hybrid reasoning model upgrading Opus 4 with improved multi-file refactoring, agentic search, and detail tracking.
Model Overview
Capabilities, design details, and architectural traits
Claude Opus 4.1 - Targeted Precision Upgrade for Agentic Coding and Deep Research
Claude Opus 4.1 is an incremental update to Claude Opus 4, narrowly focused on three documented areas: agentic task performance, real-world coding, and reasoning. It is a hybrid reasoning model, toggling between standard and extended thinking mode (up to 64K tokens), which outputs a visible chain-of-thought for harder problems. It carries the same ASL-3 deployment standard as Opus 4, with voluntary safety evaluations confirming a consistent risk profile rather than a full Responsible Scaling Policy reassessment.
| Trait | Detail |
|---|---|
| Multi-file code refactoring | Documented improvement specifically on multi-file refactoring tasks, with precision in pinpointing corrections without introducing new bugs |
| Agentic search and detail tracking | Explicitly improved for in-depth research and data analysis, particularly around detail tracking across long agentic workflows |
| Hybrid reasoning with extended thinking | Supports both fast standard responses and a visible extended thinking mode |
| ASL-3 with incremental safety scope | Deployed under ASL-3 protections; system card is an addendum to the Claude 4 card rather than a full reassessment, as the model did not meet the "notably more capable" threshold |
Upgrade Path Positioned Over Opus 4
Anthropic explicitly recommends replacing all Opus 4 usage with Opus 4.1, with the same API footprint. The system card formally classifies the changes as incremental improvements in reasoning quality, instruction-following, and overall performance - not a capability-tier shift.
Benchmark Performance
Independent evaluations · Artificial Analysis
Accuracy & Capability Details
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| Model Details | |||
|---|---|---|---|
| General Info | |||
| Provider | Anthropic | Anthropic | Anthropic |
| Release Date | August 5, 2025 | September 22, 2026 | September 28, 2026 |
| Knowledge Cutoff | Jan 2025 | - | Jun 2026 |
| Context & Limits | |||
| Context Window | 200K | 1M Best Context Window | 1M Best Context Window |
| Pricing (per 1M tokens) | |||
| Input Pricing | $15 | $4 | $2 Best Input Pricing |
| Output Pricing | $75 | $20 | $10 Best Output Pricing |
| Modalities | |||
| Inputs | imagetextfile | textimagefile | textimagefile |
| Outputs | text | text | text |
| Benchmarks (0-100) | |||
| Intelligence Index | 18.6 | 57.6 Best Intelligence Index | 56.0 |
| 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.
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