Claude Opus 4.5
Claude Opus 4.5 by Anthropic is a hybrid reasoning model for coding, agents, and computer use, with a developer-facing effort parameter and token efficiency.
Model Overview
Capabilities, design details, and architectural traits
Claude Opus 4.5 - Effort-Controlled Hybrid Reasoning
Claude Opus 4.5 is Anthropic's hybrid reasoning model built for coding, autonomous agents, and computer use. Its defining architectural addition is the effort parameter - a developer-facing API control (low / medium / high) that directly governs how many tokens and how much reasoning the model allocates per task.
| Differentiator | Detail |
|---|---|
| Effort parameter | API-exclusive low / medium / high control over reasoning depth and token spend; exclusive to Opus 4.5 at launch |
| Token efficiency at scale | Solves harder problems using fewer tokens than predecessors; cutting token usage in half on code migration and refactoring tasks |
| Computer use - zoom tool | Supports a dedicated zoom tool allowing the model to request a zoomed region of the screen during computer-use tasks |
| Context compaction | Automatically summarizes earlier context in long conversations to prevent hard cutoffs in extended agentic sessions |
| Prompt injection resistance | Documented in the system card |
| AI Safety Level 3 | Released under ASL-3 Standard of protections |
Efficiency as a First-Class Design Principle
Opus 4.5's token efficiency is not a side effect - it is a deliberate design outcome. Smarter models backtrack less and explore less redundantly, so the same reasoning quality costs fewer tokens. The effort parameter makes this explicit: developers can tune performance against spend for each workload, rather than paying for maximum reasoning on every call. Combined with context compaction and programmatic tool calling, the model is purpose-built for long-running, low-intervention agentic sessions.
Benchmark Performance
Independent evaluations · Artificial Analysis
Accuracy & Capability Details
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| Model Details | |||
|---|---|---|---|
| General Info | |||
| Provider | Anthropic | Anthropic | Anthropic |
| Release Date | November 24, 2025 | September 22, 2026 | September 28, 2026 |
| Knowledge Cutoff | - | - | Jun 2026 |
| Context & Limits | |||
| Context Window | 200K | 1M Best Context Window | 1M Best Context Window |
| Pricing (per 1M tokens) | |||
| Input Pricing | $5 | $4 | $2 Best Input Pricing |
| Output Pricing | $25 | $20 | $10 Best Output Pricing |
| Modalities | |||
| Inputs | fileimagetext | textimagefile | textimagefile |
| Outputs | text | text | text |
| Benchmarks (0-100) | |||
| Intelligence Index | 23.7 | 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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