Model evaluation report
Claude Opus 5.5 System Card
Anthropic · Published 2026-09-22
A system card is the model developer’s report describing the model, its evaluations, and its limitations.
Evidence from this source
| Type | Evidence |
|---|---|
| Result | CoBench · Claude Opus 5Source detailsSection 2.3.4.1, printed pages 36–37; PDF indices 35–36; Figure 2.3.4.1.A |
| Result | CoBench · Claude Mythos 5.1Source detailsSection 2.3.4.1, printed pages 36–37; PDF indices 35–36; Figure 2.3.4.1.A |
| Result | CoBench · Claude Opus 5.5Source detailsSection 2.3.4.1, printed pages 36–37; PDF indices 35–36; Figure 2.3.4.1.A |
| Result | CoBench · Claude Opus 5Source detailsSection 2.3.4.1, printed pages 36–37; PDF indices 35–36; Figure 2.3.4.1.A |
| Result | CoBench · Claude Mythos 5.1Source detailsSection 2.3.4.1, printed pages 36–37; PDF indices 35–36; Figure 2.3.4.1.A |
| Benchmark | CoBenchSource detailsSection 2.3.4.1, Figure 2.3.4.1.A; printed pages 36–37, PDF indices 35–36 |
| Paper / report | Claude Opus 5.5 System CardSource detailsPrimary publication source |
Document tracking details
- Source ID
- src-opus55
- Source type
- Primary
- Original URL
- https://www.anthropic.com/claude-opus-5-5-system-card
- Last updated by publisher
- Not reported
- Access status
- available
- Retrieved
- 2026-09-26T04:47:27Z
- Document fingerprint
- 7311c9c6bbb16d012f1c12c7418b05949fcf7ae3e30d2c40f22050074b2a7378
Based on original bytes. Used to detect changes to the source.
Availability checks
- 2026-09-26T04:47:27Z · success: Original source inspected by Codex; extraction check, not experimental replication.