Anthropic: Claude Opus 4.5 API
Claude 4.5 Opus is Anthropic’s most capable model to date. It excels at tackling high-complexity tasks such as frontier scientific research, intricate software architecture design, and deep strategic analysis. Compared to its predecessors, it offers significantly improved reasoning coherence and a substantial reduction in hallucinations. The Opus variant is specifically enhanced for cross-modal synthesis, enabling it to correlate details across thousands of pages of documents, massive codebases, and high-definition video streams simultaneously. It also features more granular "Constitutional AI" guardrails, ensuring the model remains helpful, harmless, and aligned with human values.
- Context window: 200,000 tokens
- Max output: 64,000 tokens
- Input: text, image, file
- Output: text
- Reasoning: Supported
- Tool calling: Supported
- File input: Supported
- Released: 2025-11-01
- Knowledge cutoff: 2025-09-01
Frequently Asked Questions
What is the context window of Claude Opus 4.5?
Claude Opus 4.5 supports a context window of up to 200,000 tokens.
Does Claude Opus 4.5 support function calling?
Yes. Claude Opus 4.5 supports tool / function calling.
Does Claude Opus 4.5 support reasoning?
Yes. Claude Opus 4.5 is a reasoning-capable model.
What is the knowledge cutoff of Claude Opus 4.5?
The knowledge cutoff of Claude Opus 4.5 is 2025-09-01.