The current product status is unsupported. Anthropic's 14 August 2026 announcement describes watermarking for future supported Claude models and a detector planned for its API. No official production detector is available to the Opace browser tools, so there is no score, threshold or pass result to report.
01 / Public research boundary
Public experiments answer a narrower question
The Google DeepMind SynthID Text reference implementation can show how a documented scheme behaves with a known configuration and key. A reproducible record also needs the source commit, licence, configuration hash, transformation and detector version. This public implementation is not Anthropic's production verifier.
02 / Transformation evidence
Why rewriting is not proof of removal
Google's SynthID guidance says detection confidence can fall after thorough rewriting or translation, but a changed public detector response does not establish transfer to Claude production output. A rewrite may also alter names, figures, links, quotations, citations or meaning, so signal movement and factual damage need separate measurements.
03 / Production evidence
The evidence needed for a production claim
An official method would need to identify the production scheme and accept the matching input, key or verification route. The test would then need recorded before-and-after outputs, matched versions and an independently checkable result. Until that route exists, “Claude verified” and “Claude watermark removed” are unsupported claims.
04 / Opace reporting method
How Opace will report a future method
The Claude Watermark Readiness Lab keeps public-fixture evidence apart from production availability. The AI Content Integrity methodology defines the canonical statuses and prevents unavailable checks from appearing as passes.