Anthropic Implements Statistical Watermarking in Fable 5.1
September 1, 2026
Fable 5.1 and Mythos 5.1 now include Anthropic's statistical text watermarking. A new verification tool is available at claude.com/check-content to detect model-generated provenance.
HOW THIS AFFECTS YOU
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builderYou should account for watermarking when building applications that require raw, undetected text outputs.
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policyYou can better track and verify AI-generated content provenance.