Per-model status
Is Claude Opus 5 watermarked?
No, Claude Opus 5 does not watermark its text output as of August 2026, because it launched before Anthropic's August 2, 2026 watermarking cutoff. Anthropic has said it will retrofit watermarking to older models, so this is expected to change.
Anthropic's text watermark applies by default to models introduced on or after the cutoff date. Opus 5 shipped before it, so its output carries no statistical watermark today. If Anthropic retrofits Opus 5, output generated after that point would be marked, while text you generated before it would not.
FAQ
Is Claude Opus 5 watermarked?
Not as of August 2026. Claude Opus 5 launched before the August 2, 2026 cutoff, so its text output carries no statistical watermark today.
Can anyone detect Claude Opus 5 output?
No. Anthropic announced a detection API but has not shipped it, and no third-party tool can read the statistical watermark. Even once it ships, only output from a marked model would be detectable.
Will Claude Opus 5 get watermarked later?
Anthropic has said it is working to add watermarking to models released before the cutoff. If that happens, output generated after the retrofit would be marked, while text you generated before it would not be.
How do I remove the watermark if Claude Opus 5 gets retrofitted?
A complete rewrite through a different, non-watermarking model breaks the statistical pattern. ClaudeRewrite does this automatically using DeepSeek V4 Flash, preserving your facts, numbers, and meaning.