Anthropic Claude: Claude Fable 5.2 API
Claude Fable 5.2 is Anthropic's model for demanding reasoning and long-horizon agentic work, such as agent sessions that run for hours, multistep deep research, and analysis carried through to a finished document, spreadsheet, or deck. It costs less than Claude Fable 5.1 for input and output, with thinking always on and depth set by the effort parameter, which defaults to high.
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Input: text, image, file
- Output: text
- Reasoning: Supported
- Tool calling: Supported
- File input: Supported
- Released: 2026-11-09
- Knowledge cutoff: 2026-06-30
Frequently Asked Questions
What is the context window of Claude Fable 5.2?
Claude Fable 5.2 supports a context window of up to 1,000,000 tokens.
Does Claude Fable 5.2 support function calling?
Yes. Claude Fable 5.2 supports tool / function calling.
Does Claude Fable 5.2 support reasoning?
Yes. Claude Fable 5.2 is a reasoning-capable model.
What is the knowledge cutoff of Claude Fable 5.2?
The knowledge cutoff of Claude Fable 5.2 is 2026-06-30.