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AIQuiet 10d · day 11

Anthropic watermarks older Claude models, but leaves bypass on two versions

EU AI Act compliance drive expands to four older models starting November 3, but API users can dodge the mark on Opus 4.6 and Sonnet 4.6 with a single parameter tweak.

newest coverage 10d agosummary written 10d ago5 pieces NewswiresMastodonReddit

What to know

  • Anthropic expands watermarks to four older Claude models starting November 3 to comply with the EU AI Act's December deadline.
  • A loophole exists on Claude Opus 4.6 and Sonnet 4.6: developers can bypass the watermark by adjusting any one of three sampling parameters (temperature, top_p, top_k).
  • Anthropic warns users to keep default settings but does not prevent the workaround, raising questions about the robustness of compliance.
  • The watermark is meant to help distinguish AI-generated text from human-written content, but effectiveness remains disputed by experts who question whether it degrades text quality.

“The watermark contains no information about the user, their organization, or their conversations with Claude.”

Anthropic, AI company · Mashable ↗

Anthropic AI company deploying watermarksJohn Gruber Blogger

Anthropic watermarks older Claude models, but leaves bypass on two versions
mashable.com

How it unfolded 2 developments, newest first · click a bar or a number to jump articlesposts

Peak 3 pieces in 3h at Nov 1, 1 PM; 5 pieces over 11 days (2 articles · 3 posts) Oct 31, 2 PM — 1 piece · 1 article — Newswires 1Oct 31, 5 PM — quietOct 31, 8 PM — quietOct 31, 11 PM — quietNov 1, 1 AM — quietNov 1, 4 AM — quietNov 1, 7 AM — quietNov 1, 10 AM — 1 piece · 1 article — Newswires 1Nov 1, 1 PM — 3 pieces · 3 posts — Mastodon 2, Reddit 1Nov 1, 4 PM — quietNov 1, 7 PM — quietNov 1, 10 PM — quietNov 2, 1 AM — quietNov 2, 4 AM — quietNov 2, 7 AM — quietNov 2, 10 AM — quietNov 2, 1 PM — quietNov 2, 4 PM — quietNov 2, 7 PM — quietNov 2, 10 PM — quietNov 3, 1 AM — quietNov 3, 4 AM — quietNov 3, 7 AM — quietNov 3, 10 AM — quietNov 3, 1 PM — quietNov 3, 4 PM — quietNov 3, 7 PM — quietNov 3, 10 PM — quietNov 4, 1 AM — quietNov 4, 4 AM — quietNov 4, 7 AM — quietNov 4, 10 AM — quietNov 4, 1 PM — quietNov 4, 4 PM — quietNov 4, 7 PM — quietNov 4, 10 PM — quietNov 5, 1 AM — quietNov 5, 4 AM — quietNov 5, 7 AM — quietNov 5, 10 AM — quietNov 5, 1 PM — quietNov 5, 4 PM — quietNov 5, 7 PM — quietNov 5, 10 PM — quietNov 6, 1 AM — quietNov 6, 4 AM — quietNov 6, 7 AM — quietNov 6, 10 AM — quietNov 6, 1 PM — quietNov 6, 4 PM — quietNov 6, 7 PM — quietNov 6, 10 PM — quietNov 7, 1 AM — quietNov 7, 4 AM — quietNov 7, 7 AM — quietNov 7, 10 AM — quietNov 7, 1 PM — quietNov 7, 4 PM — quietNov 7, 7 PM — quietNov 7, 10 PM — quietNov 8, 1 AM — quietNov 8, 4 AM — quietNov 8, 7 AM — quietNov 8, 10 AM — quietNov 8, 1 PM — quietNov 8, 4 PM — quietNov 8, 7 PM — quietNov 8, 10 PM — quietNov 9, 1 AM — quietNov 9, 4 AM — quietNov 9, 7 AM — quietNov 9, 10 AM — quietNov 9, 1 PM — quietNov 9, 4 PM — quietNov 9, 7 PM — quietNov 9, 10 PM — quietYesterday, 1 AM — quietYesterday, 4 AM — quietYesterday, 7 AM — quietYesterday, 10 AM — quietYesterday, 1 PM — quietYesterday, 4 PM — quietYesterday, 7 PM — quietYesterday, 10 PM — quietToday, 1 AM — quietToday, 4 AM — quietToday, 7 AM — quietToday, 10 AM — quietToday, 1 PM — quietToday, 4 PM — quiet 12
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  1. 2

    Mashable reports watermark rollout begins November 3

    Mashable confirmed Anthropic's Friday announcement that older Claude versions will receive watermarks, noting this is the second phase of compliance after the initial August rollout.

    1. 1 outlet Anthropic expands text watermarking to older Claude versions beginning November 3

      first by Mashable, 10d ago

  2. 1

    Anthropic announces watermark expansion with loophole on older models

    Anthropic notified API customers it would expand watermarks to Claude Mythos 5, Opus 4.7, Opus 4.6, and Sonnet 4.6, starting November 3. On Opus 4.6 and Sonnet 4.6, users can disable the watermark by tweaking temperature, top_p, or top_k sampling parameters.

    “If you rely on the watermark for your own compliance, keep these settings at their defaults.”
    — Anthropic

    1. 1 outlet first by The Decoder, 11d ago · read ↗

  3. background

    Anthropic begins watermarking new Claude models — Anthropic started watermarking all Claude models released after August 2, 2026, embedding an imperceptible pattern in word choice to comply with EU AI Act requirements.