Model · Multimodal language model
Claude Opus 4.8
A pinned multimodal Claude release in legacy status, available through Anthropic's developer API and documented third-party cloud platforms, without downloadable model weights.
- Developer
- Anthropic
- Distribution
- Developer API · Third-party hosting
- Artifact licensing
- Proprietary access
- License scope
- Reviewed release artifacts and mandatory terms; not an assessment of training code or training data openness.
- Licenses
- Anthropic Commercial Terms of Service
- Boundary
- This record represents the fixed Claude Opus 4.8 model release identified by the dateless pinned ID claude-opus-4-8, which Anthropic documents as a single fixed snapshot rather than an alias. Anthropic's API, Amazon Bedrock, Google Cloud, Microsoft Foundry, Claude Platform on AWS, Claude applications, and Claude Opus 5 and later Opus releases remain separate service or product boundaries.
Risk statements
“CB-1” · Precautionary
Non-novel chemical and biological weapons (CB-1): We believe it is hard to be confident whether a model passes this threshold, but (as with previous recent models) our results are consistent with Opus 4.8 providing significant uplift to individuals or groups with basic technical backgrounds for this threat model.
- Risk areas
- Biological or chemical
- Covers
- The model itself
Read the developer's statement ↗ · 2026-10-07 · Research confidence: High
Anthropic names this release against “CB-1” in biological or chemical capability, as a precaution. The statement covers the model itself. This is the developer's own statement, not an Atlas risk rating.
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