Claude Opus 4.5 (May 2025)
Claude Opus 4.5 (May 2025) is the dated-release version of Anthropic's Opus 4.5 flagship model, pinned to the May 14, 2025 checkpoint for reproducibility. As the most capable model in Anthropic's 4.x generation, Opus 4.5 is designed for the most demanding agentic, reasoning, and analytical workloads where maximizing quality is the primary goal.
This dated model ID is intended for enterprise teams and researchers who need version-stable behavior across long-running pipelines or evaluation benchmarks. It inherits the full capability set of Claude Opus 4.5 — including extended thinking, robust tool use, and sophisticated multi-step reasoning — while providing a guaranteed stable API target.
Key Features
Anthropic's highest-capability Opus 4.5 model in a pinned checkpoint
Extended thinking support for deep, multi-step reasoning tasks
Robust multi-tool orchestration for complex agentic workflows
Strong performance on coding, analysis, and research synthesis
Version-stable API target for reproducible evaluation pipelines
Handles nuanced, high-stakes tasks requiring accurate reasoning
Ideal Use Cases
Long-running enterprise agentic pipelines requiring stable outputs
Evaluation and benchmarking against a fixed model checkpoint
Advanced code generation and architectural problem-solving
Complex research analysis and multi-document synthesis
High-stakes decision-support applications in legal or scientific domains
Example Prompts for Claude Opus 4.5 (May 2025)
Technical Specifications
| Provider | Anthropic |
| Category | Text |
| Modality | Text -> Text |
| Context Window | 200K tokens |
Frequently Asked Questions
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