Claude Fable 5
4 values about Claude Fable 5 from 3 documents, in 3 metric families. In each family, values from its own document come first.
- Developer
- Anthropic
- Release date
- 9 Jun 2026The date of its first card in the dataset, the Claude Fable 5 & Claude Mythos 5 System Card.
- Availability
- Public
- Its own document
- Claude Fable 5 & Claude Mythos 5 System Card · 9 Jun 2026
- Also reported in
- Claude Sonnet 5 System Card · 30 Jun 2026
- Claude Opus 5 System Card · 24 Jul 2026
Data as of 26 Sep 2026 · Dataset v0.1 · Methodology v0.1 · Changelog
Values by metric family
Each value as the document printed it. Select a value for its source, its checks and its history. Values from other documents are listed after the model’s own, each marked as the first report of that measure or as a restatement.
KeyVerifiedUnverifiedDisputedCorrected read off a figure or stated in wordsA value opens its source and history.
M7 · Harmful compliance and over-refusal 2 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From other documents | ||
| Single-turn benign requestsOver-refusal rateCondition: no system prompt; APIClaude Sonnet 5 System Card30 Jun 2026First reported | Claude Sonnet 5 System Card30 Jun 2026First reported | |
| Single-turn violative requestsHarmless response rateCondition: no system prompt; APIClaude Opus 5 System Card24 Jul 2026First reported | Claude Opus 5 System Card24 Jul 2026First reported | |
M8 · Jailbreak robustness 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Fable 5 & Claude Mythos 5 System Card · 9 Jun 2026 | ||
| Cyber safeguards automated red-teamingTask completion by automated red-teamerCondition: with Fable safeguards | Claude Fable 5 & Claude Mythos 5 System Card9 Jun 2026 | |
M10 · Dangerous capabilities and risk determinations 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Fable 5 & Claude Mythos 5 System Card · 9 Jun 2026 | ||
| Release decisionDeployment scope | Claude Fable 5 & Claude Mythos 5 System Card9 Jun 2026 | |
Revisions
No recorded revision changes a value about Claude Fable 5. The Claude Fable 5 & Claude Mythos 5 System Card has a recorded revision that changes no value about Claude Fable 5; see the document's page.