Anthropic: Claude Fable 5 API

Anthropic's most capable widely released model, for the most demanding reasoning and long-horizon agentic work

Frequently Asked Questions

What is the context window of Claude Fable 5?

Claude Fable 5 supports a context window of up to 1,000,000 tokens.

Does Claude Fable 5 support function calling?

Yes. Claude Fable 5 supports tool / function calling.

Does Claude Fable 5 support reasoning?

Yes. Claude Fable 5 is a reasoning-capable model.

What is the knowledge cutoff of Claude Fable 5?

The knowledge cutoff of Claude Fable 5 is 2025-11-30.