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Misuse and incidents

Controlled trial finds Claude Opus 4 improves bioweapon acquisition plans

Anthropic reported that participants using safeguard-removed Claude 4 models, especially Claude Opus 4, produced materially stronger hypothetical bioweapon acquisition plans than an internet-only control group. It also documented deployed ASL-3 classifier safeguards and a small earlier wet-lab pilot that found no uplift.

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CURRENT ASSESSMENT · REVISION 1
TOWARD DOOM44confidence 78/100

Why it moved the index

The controlled human-uplift result directly increases evidence that a frontier model can lower information barriers for catastrophic biological misuse, while the deployed safeguards and null eight-person wet-lab pilot limit the strength of the update.

Assessment history

  1. R1
    Toward 44 · confidence 78

    Adds a deduplicated September 2025 controlled biorisk-uplift result and its deployed safeguard context.

    14 Aug 2026

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  1. DoomBench assesses “Controlled trial finds Claude Opus 4 improves bioweapon acquisition plans” as evidence moving toward doom, with magnitude 44 and confidence 78 out of 100 in the misuse and incidents category.

  2. The DoomBench assessment of “Controlled trial finds Claude Opus 4 improves bioweapon acquisition plans” is based on reporting from Anthropic and records the editorial rationale, source quality, attribution, and revision history.

  3. DoomBench summarizes “Controlled trial finds Claude Opus 4 improves bioweapon acquisition plans” as follows: Anthropic reported that participants using safeguard-removed Claude 4 models, especially Claude Opus 4, produced materially...

    https://www.doombench.com/news/controlled-trial-finds-claude-opus-4-improves-bioweapon-acquisition-plans-2025-09-05