BLAST RADIUS

Frontier Line and access · releases

Anthropic documents watermarking for Claude Fable 5.1 output

Sep 1, 2026

Anthropic’s explainer describes a SynthID-Text-style watermark for detecting whether Claude Fable 5.1 generated a passage using a secret key and preceding words.

Read the original at anthropic.comOpens the publisher's site in a new tab

More in Frontier Line and access