Claude Adds Machine-Readable Marks
Anthropic says supported Claude models will embed watermarks in text and attach signed provenance to supported files as EU AI Act transparency duties take effect.
The 60-second version
Anthropic is adding embedded text watermarks and signed file provenance to supported Claude output as EU transparency duties take effect.
Key points
- Supported generated text carries an imperceptible model-level watermark that can travel with copy and paste.
- Supported SVG, PNG, and JPEG files can carry signed C2PA metadata that records Claude processing and supports tamper checks.
- New models launched on or after August 2, 2026 support marking at launch, while support for older models is still being added.
- Coverage is worldwide across supported Claude products, APIs, and cloud access, but some file types and platforms may not support every mark.
- A detected mark suggests Claude processing; it does not prove original authorship, and no detected mark does not prove human origin.
Verdict. The policy creates useful provenance signals, but its operational value cannot be judged fully until Anthropic publishes detector access, accuracy, and robustness details.
The changeTwo signals for two content types
Anthropic says supported Claude models will place an imperceptible watermark inside generated text and attach digitally signed C2PA provenance metadata to supported files. The text signal is applied at the model level; file marking depends on the format and platform supporting provenance metadata.
MechanismHow the marks travel
| Generated text | An invisible signal is woven into the text, travels with copy and paste, and may survive some editing. |
|---|---|
| Supported files | SVG, PNG, and JPEG examples can carry signed C2PA provenance metadata that also supports tamper checks. |
| Product surfaces | Supported models are covered across Claude, Claude Platform, Claude Code, Claude Cowork, and Claude Tag. |
| Cloud access | Text marks extend to supported models through AWS, Google Cloud, and Microsoft Foundry; file provenance may vary. |
InterpretationA mark is a signal, not an authorship certificate
A detected Claude mark indicates that content may have been processed by Claude. It does not establish who created the underlying ideas or whether the material changed later. An absent mark is equally inconclusive: older models, heavy editing, paraphrasing, translation, very short passages, unsupported workflows, and stripped file metadata can remove or weaken the evidence.
RegulationWhat the EU framework requires
Article 50 requires machine-readable transparency signals; it does not turn a watermark into conclusive proof of authorship.