Model · Multimodal language model
Claude Opus 4.5
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 4.5 snapshot identified by claude-opus-4-5-20251101, which the pre-4.6 alias claude-opus-4-5 resolves to. Anthropic's API, Amazon Bedrock, Google Cloud, Microsoft Foundry, Claude Platform on AWS, Claude applications, and later Opus releases remain separate service or product boundaries.
Risk statements
“ASL-3” · Safeguard standard
In particular, Claude Opus 4.5 outperformed Claude Opus 4.1 and Claude Sonnet 4.5 models on both long-form virology tasks, as well as on several subtasks of the DNA synthesis screening evaluation, while achieving comparable performance on all other evaluations. As a result, we determined ASL-3 safeguards were appropriate.
- Risk areas
- Biological or chemical
- Covers
- The model itself
Read the developer's statement ↗ · 2026-10-07 · Research confidence: High
Anthropic states that this release ships under the “ASL-3” safeguard standard for biological or chemical capability. The statement covers the model itself. This is the developer's own statement, not an Atlas risk rating.
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