Shadow 06 / Figure 6
Providers, one table
Scroll the table sideways to see every column.
| Field | Anthropic | OpenAI | |
|---|---|---|---|
| Image / video / audio mark | C2PA signatures on supported generated files; separate multimedia watermark not found | SynthID watermark (portal also checks partners' content) | SynthID watermark + C2PA metadata on images; supported audio since Jul 2026 |
| Text mark | A version of SynthID-Text on supported models, worldwide subject to model/feature/platform support | SynthID-Text | Text watermark: ChatGPT/Codex text marked by default in the EU only; API opt-in, off by default |
| Who can check (hosted) | Files: free content checker + C2PA tools; text: detection API in private preview | Public portal for images, video, audio | Images and audio: public verifier + API; text detector: approved researchers only |
| Detector code / verification tooling | Text production-detector source: not found. File credentials: verification with compatible C2PA tooling is documented, including the open-source c2patool. | SynthID-Text reference code public, incl. detection ("not intended for production") | Announced intent to open-source |
| Published text robustness evaluation | No Claude-specific numerical robustness evaluation comparable in reporting form to the other table entries was found | Peer-reviewed (Nature 2024): evaluation incl. edits and paraphrasing; numbers in Supplementary C.6 | Provider's own (5 Oct 2026), 1% FPR target: ~80% detected at 200 tokens, ~95% at 400 tokens (psychology); lower for mathematics. Synonym substitution on 400-token English answers: 10% of words → 92% to 66%; 25% → 17% |
| Self-stated limits | Short text weaker; mark is not complete authorship; missing credentials not human origin | Watermarks weakened by edits; vulnerable to stealing, spoofing and scrubbing; coordination among providers can broaden coverage | Absence of a mark does not establish human authorship |
Footnote 1
Each provider's column had an independent reviewer; see Method.
Footnote 2
Figures come from different implementations, corpora and operating points. No ranking is implied.
Footnote 3
"Not found" means not located in the stated review; it does not establish non-existence, concealment, unlawfulness or non-compliance.
SOURCE · Anthropic: Claude Help Centre, "How Claude marks AI-generated content"; Claude Platform documentation (code execution tool); Anthropic, text-watermark announcement — retrieved Oct 2026
SOURCE · Google: Google blog, 7 Oct 2026 (SynthID Detector); Dathathri et al., Nature 634 (2024); github.com/google-deepmind/synthid-text
SOURCE · OpenAI: OpenAI, "Advancing content provenance" (19 May 2026, update 31 Jul 2026); OpenAI, "Our approach to EU text provenance rules" (5 Oct 2026)