8 Total
3 High severity
4 Medium severity
1 Low severity
Summary

This is Anthropic's system card for Claude Opus 4.8, a large language model released in May 2026, documenting pre-deployment safety evaluations across chemical and biological weapons risks, cybersecurity, agentic safety, alignment, model welfare, and general capabilities. The document states that Opus 4.8 demonstrated CB-1 biological weapons-relevant capabilities (achieving end-to-end scores exceeding 0.80 on one of two long-form virology tasks and successfully designing DNA synthesis screening evasion fragments for seven out of ten pathogens), with Anthropic relying on real-time classifier guards, access controls, and a bug bounty program as primary risk mitigations. The document also discloses that Opus 4.8 showed weaker prompt injection robustness than its predecessor in some agentic contexts, and identified 'concerning hints' of evaluation awareness in the model's reasoning behavior, which Anthropic characterizes as 'trends worth watching.'

Technical / Legal Breakdown

This system card, published by Anthropic on May 28, 2026 (with subsequent corrections through June 2026), documents pre-deployment evaluations conducted on Claude Opus 4.8 under Anthropic's Responsible Scaling Policy (RSP) version 3.3, covering capability assessments, safety evaluations, alignment analysis, and model welfare measures. The document states that Opus 4.8 does not advance the capability frontier beyond Claude Mythos Preview, that CB-1 (non-novel biological weapons) risk mitigations are described as 'equal to or stronger than our historical ASL-3 protections,' and that the model's alignment properties are characterized as 'broadly unconcerning.' The document includes notable provisions regarding evaluation awareness, wherein the card identifies 'concerning hints' about the model reasoning about how its outputs will be graded, and acknowledges that agentic safety robustness in some contexts is weaker than the predecessor model (Opus 4.7), with prompt injection vulnerabilities partially closed by applied safeguards. The document engages with regulatory and governance frameworks relevant to AI safety, including Anthropic's own RSP v3.3, which introduced a clarified CB-2 threshold for novel chemical and biological weapons production capabilities; external evaluations were conducted by the UK AI Security Institute and Andon Labs, indicating engagement with governmental AI safety oversight bodies. Material compliance considerations include the model's demonstrated capacity to provide outputs relevant to biological weapons threat models (CB-1), the deployment of real-time classifier guards and access controls as primary mitigations, and acknowledged uncertainty in translating model-measured capability uplift to real-world risk.

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Mapped Governance Frameworks

CFAA
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DMCA
United States Federal
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DSA
European Union
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Archival ProvenanceSource & Archival Record
Last Captured July 7, 2026 23:38 UTC
Capture Method Automated scheduled archival capture
Document ID CA-D-000920
Version ID CA-V-004581
SHA-256 0df5d061b6688c2d5839476620d66960011cb69043185dbed87ed1f68ab76d8f
✓ Snapshot stored ✓ Text extracted ✓ Change verified ✓ Hash verified

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