Messages API

Assess

Platforms

Anthropic's API for multi-turn conversations and preserved thinking blocks.

Why it's here

Placed in Assess: 1 article(s) of evidence from 1 source(s), led by product launches, with 0 in the last 30 days. Confidence 24%. Low accumulated evidence, so it defaults conservatively pending more signal.

Evidence (1)

7The New Stack·9/1/2026product_launch
Claude Fable 5.1 adds watermarking with code limitations
Anthropic has launched Claude Fable 5.1 with a statistical watermark designed to help detect AI-generated text, using a method based on token-randomness changes rather than metadata. The watermark is more effective on natural language than code, and Anthropic is also tightening how preserved thinking blocks can be reused to reduce model distillation risk.