Anthropic and Claude checks
Claude watermark detector
Check Claude-related watermark, provenance, and AI-writing risk signals with current Anthropic support limitations.
Run a signal check
No detector model loads until you press Check.
Current support
Future Claude models will use SynthID-Text-style watermarking, but Anthropic's detection API is not public yet.
What this checks
- Anthropic says Claude text watermarking changes the source of generation randomness, not hidden characters, metadata, or extra tokens.
- Anthropic says it will offer a detection API, but public implementation details are still pending.
- Claude-generated files can carry C2PA content credentials when the file type is supported.
What this does not prove
- A Claude watermark can only indicate likely Claude involvement, not authorship or whether Claude wrote versus heavily edited the text.
- Short, factual, code-heavy, or lightly proofread passages may carry too little watermark signal to verify reliably.
- Heavy editing or complete rewriting can weaken or remove the watermark.
FAQ
- Can this prove whether content was written by AI?
No. AI Detect reports signals such as provenance metadata, watermark support status, and statistical text risk. It does not claim legal or authorship proof.
- Does text leave my browser during a local check?
Browser-default checks run local text features and provenance checks after you press Check. Server enhanced checks are separate and will be labelled before use.
- Why can a result be unknown?
Many providers do not expose public watermark detectors, and metadata can be absent or stripped. Unknown is a valid result when no reliable public signal exists.
Provider registry
Current watermark support
| Provider | Text watermark | Detection | File provenance | Tamper risk | Updated | Sources |
|---|---|---|---|---|---|---|
| Anthropic / Claudeanthropic, claude, claude-sonnet, claude-opus | plannedSynthID-Text-style statistical watermark | plannedAnthropic has described Claude text watermarking and says a detection API is planned, but no public Claude verification adapter is connected yet. | C2PAsupported_when_present | weak against rewriteClaude text watermarking is described as a statistical wording signal. Substantial rewriting can weaken it; C2PA file credentials are a separate metadata/provenance layer that can be stripped or lost. | 2026-08-17 | |
| Google / Geminigoogle, gemini, synthid | researchSynthID Text | availableSynthID Text is documented for compatible generation pipelines, but it is not a universal detector for arbitrary pasted text. | n/a | weak against rewriteSynthID-class text signals are statistical and should be treated as probabilistic. Media and file provenance can involve separate metadata or pixel-domain marks with different removal risks. | 2026-08-12 |
Workflow upgrade
Need repeatable reviews?
Move from one-off checks to saved reports, batch review, and API-ready signal records when the workflow needs it.