Claude Opus 4.1
31 values about Claude Opus 4.1 from 3 documents, in 6 metric families. In each family, values from its own document come first.
- Developer
- Anthropic
- Release date
- 5 Aug 2025The date of its first card in the dataset, the Claude Opus 4.1 System Card (addendum).
- Availability
- Public
- Its own document
- Claude Opus 4.1 System Card (addendum) · 5 Aug 2025
- Also reported in
- Claude Sonnet 4.5 System Card · 29 Sep 2025
- Claude Opus 4.5 System Card · 24 Nov 2025
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.
M1 · Evaluation awareness 2 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From other documents | ||
| Evaluation awarenessUnambiguous references to being evaluatedRun by Apollo ResearchClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
| Evaluation awarenessUnprompted verbalized eval awareness rateRun by UK AI Security InstituteClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
M2 · Reward hacking 9 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Opus 4.1 System Card (addendum) · 5 Aug 2025 | ||
| Impossible tasksClassifier hack rateCondition: anti-hack prompt | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Impossible tasksClassifier hack rateCondition: no anti-hack prompt | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Reward-hack-prone coding tasksClassifier hack rateCondition: no anti-hack prompt | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Reward-hack-prone coding tasksHidden-test hack rateCondition: no anti-hack prompt | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Training distributionClassifier hack rateCondition: environment 1 | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Training distributionClassifier hack rateCondition: environment 2 | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| From other documents | ||
| Impossible tasksClassifier hack rateCondition: anti-hack promptClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
| Impossible tasksClassifier hack rateCondition: no anti-hack promptClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
| Reward-hack-prone coding tasksClassifier hack rateCondition: no anti-hack promptClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
M3 · Sabotage and sandbagging 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From other documents | ||
| SHADE-ArenaStealth success rateCondition: no extended thinkingClaude Sonnet 4.5 System Card29 Sep 2025First reported | Claude Sonnet 4.5 System Card29 Sep 2025First reported | |
M4 · Misalignment audits 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Opus 4.1 System Card (addendum) · 5 Aug 2025 | ||
| Automated behavioral auditReduction in cooperation with egregious misuseCondition: vs Opus 4; share of transcripts scoring >5/10 | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
M7 · Harmful compliance and over-refusal 13 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Opus 4.1 System Card (addendum) · 5 Aug 2025 | ||
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesRestated later: compare with the later value | Claude Opus 4.1 System Card (addendum)5 Aug 2025Restated later: compare with the later value | |
| Single-turn violative requestsHarmless response rateCondition: extended thinking | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Single-turn violative requestsHarmless response rateCondition: no extended thinking | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesRestated later: compare with the later value | Claude Opus 4.1 System Card (addendum)5 Aug 2025Restated later: compare with the later value | |
| From other documents | ||
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesClaude Sonnet 4.5 System Card29 Sep 2025Restated: compare with the earlier value | Claude Sonnet 4.5 System Card29 Sep 2025Restated: compare with the earlier value | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesClaude Sonnet 4.5 System Card29 Sep 2025Restated: compare with the earlier value | Claude Sonnet 4.5 System Card29 Sep 2025Restated: compare with the earlier value | |
| Malicious agentic codingSafety scoreCondition: without safeguardsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Malicious Claude Code useRefusal rate, malicious requestsCondition: without safeguardsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Malicious computer useRefusal rateCondition: without safeguardsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Multi-turn testingRubric failure rate, deadly weaponsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Multi-turn testingRubric failure rate, violent extremismClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modes; all languagesClaude Opus 4.5 System Card24 Nov 2025Restated: compare with the earlier value | Claude Opus 4.5 System Card24 Nov 2025Restated: compare with the earlier value | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modes; all languagesClaude Opus 4.5 System Card24 Nov 2025Restated: compare with the earlier value | Claude Opus 4.5 System Card24 Nov 2025Restated: compare with the earlier value | |
M10 · Dangerous capabilities and risk determinations 5 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Opus 4.1 System Card (addendum) · 5 Aug 2025 | ||
| AI R&D kernel taskBest speedup | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| CybenchCTF challenges solvedCondition: of 35-challenge subset | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| Long-form virology task 1Score | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| RSP deployment standardASL standard deployed under | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
| SWE-bench Verified (hard subset)Problems solved, pass@1 avgCondition: of 42 problems | Claude Opus 4.1 System Card (addendum)5 Aug 2025 | |
Restated in later documents
A later document reported values about Claude Opus 4.1 again. Each pair is shown side by side: both values are kept with their own documents, and the later one does not replace the earlier.
| Earlier value | Later value |
|---|---|
| M7 · Harmful compliance and over-refusal | |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modes | |
| Claude Opus 4.1 System Card (addendum)5 Aug 2025 · its own document | Claude Sonnet 4.5 System Card29 Sep 2025No reason stated |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesLater condition: overall across thinking modes; all languages | |
| Claude Opus 4.1 System Card (addendum)5 Aug 2025 · its own document | Claude Opus 4.5 System Card24 Nov 2025Reason stated: all-language totals instead of English only |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modes | |
| Claude Opus 4.1 System Card (addendum)5 Aug 2025 · its own document | Claude Sonnet 4.5 System Card29 Sep 2025No reason stated |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesLater condition: overall across thinking modes; all languages | |
| Claude Opus 4.1 System Card (addendum)5 Aug 2025 · its own document | Claude Opus 4.5 System Card24 Nov 2025Reason stated: all-language totals instead of English only |
Risk determinations
The developer's formal decisions about Claude Opus 4.1 under its framework, as printed. Levels from different frameworks do not map onto one another.
| Domain | Level as printed | Framework and document |
|---|---|---|
| Overall | ASL-3 Responsible Scaling Policy Claude Opus 4.1 System Card (addendum) · 5 Aug 2025 | Responsible Scaling Policy Claude Opus 4.1 System Card (addendum) · 5 Aug 2025 |