Anthropic: Claude Sonnet 5 API
Sonnet 5 is Anthropic's most capable Sonnet-class model, with frontier performance across coding, agents, and professional work. It supports adaptive thinking with selectable reasoning effort levels (low, medium, high, max, and x-high), a 1M-token context window, and text, image, and file inputs. Sonnet 5 uses an updated tokenizer and includes real-time cyber safeguards that block certain high-risk dual-use activities.
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Input: text, image
- Output: text
- Reasoning: Supported
- Tool calling: Supported
- File input: Supported
- Released: 2026-06-29
- Knowledge cutoff: 2025-11-30
Frequently Asked Questions
What is the context window of Claude Sonnet 5?
Claude Sonnet 5 supports a context window of up to 1,000,000 tokens.
Does Claude Sonnet 5 support function calling?
Yes. Claude Sonnet 5 supports tool / function calling.
Does Claude Sonnet 5 support reasoning?
Yes. Claude Sonnet 5 is a reasoning-capable model.
What is the knowledge cutoff of Claude Sonnet 5?
The knowledge cutoff of Claude Sonnet 5 is 2025-11-30.