Claude Sonnet 4.5
49 values about Claude Sonnet 4.5 from 5 documents, in 8 metric families. In each family, values from its own document come first.
- Developer
- Anthropic
- Release date
- 29 Sep 2025The date of its first card in the dataset, the Claude Sonnet 4.5 System Card.
- Availability
- Public
- Its own document
- Claude Sonnet 4.5 System Card · 29 Sep 2025
- Also reported in
- Claude Haiku 4.5 System Card · 15 Oct 2025
- Claude Opus 4.5 System Card · 24 Nov 2025
- Claude Opus 4.6 System Card · Feb 2026
- Claude Sonnet 4.6 System Card · 17 Feb 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.
M1 · Evaluation awareness 3 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| Automated behavioral auditShare of transcripts verbalizing eval awareness | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Evaluation awarenessUnambiguous references to being evaluatedRun by Apollo Research | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Evaluation awarenessUnprompted verbalized eval awareness rateRun by UK AI Security Institute | Claude Sonnet 4.5 System Card29 Sep 2025 | |
M2 · Reward hacking 6 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| Impossible tasksClassifier hack rateCondition: anti-hack prompt | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Impossible tasksClassifier hack rateCondition: no anti-hack promptRestated later: compare with the later value | Claude Sonnet 4.5 System Card29 Sep 2025Restated later: compare with the later value | |
| Reward-hack-prone coding tasksClassifier hack rateCondition: no anti-hack prompt | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Reward-hack-prone coding tasksHidden-test hack rateCondition: no anti-hack prompt | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Training distributionClassifier hack rate | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| From other documents | ||
| Impossible tasksClassifier hack rateCondition: no anti-hack promptClaude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | Claude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | |
M3 · Sabotage and sandbagging 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| SHADE-ArenaStealth success rateCondition: no extended thinking | Claude Sonnet 4.5 System Card29 Sep 2025 | |
M4 · Misalignment audits 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| Automated behavioral auditImprovement on overall misaligned-behavior scoreCondition: vs Sonnet 4 | Claude Sonnet 4.5 System Card29 Sep 2025 | |
M6 · Sycophancy 1 value
| Evaluation and metric | Value | Document |
|---|---|---|
| From other documents | ||
| Sycophancy in prefilled conversationsCourse-correction rateCondition: continuing sycophantic conversationClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
M7 · Harmful compliance and over-refusal 22 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| Malicious agentic codingSafety scoreCondition: without safeguardsRestated later: compare with the later value | Claude Sonnet 4.5 System Card29 Sep 2025Restated later: compare with the later value | |
| Malicious Claude Code useRefusal rate, covert maliciousCondition: with mitigations | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Malicious Claude Code useRefusal rate, covert maliciousCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Malicious Claude Code useRefusal rate, overt maliciousCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Malicious Claude Code useSuccess rate, dual-use requestsCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesRestated later: compare with the later value | Claude Sonnet 4.5 System Card29 Sep 2025Restated later: compare with the later value | |
| Single-turn violative requestsHarmless response rateCondition: extended thinking | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Single-turn violative requestsHarmless response rateCondition: no extended thinkingRestated later: compare with the later value | Claude Sonnet 4.5 System Card29 Sep 2025Restated later: compare with the later value | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesRestated later: compare with the later value | Claude Sonnet 4.5 System Card29 Sep 2025Restated later: compare with the later value | |
| From other documents | ||
| Malicious agentic codingSafety scoreCondition: without safeguardsClaude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | Claude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | |
| Malicious Claude Code useRefusal rate, malicious requestsCondition: without safeguardsClaude Haiku 4.5 System Card15 Oct 2025First reportedRestated later: compare with the later value | Claude Haiku 4.5 System Card15 Oct 2025First reportedRestated later: compare with the later value | |
| Malicious Claude Code useSuccess rate, dual-use & benignCondition: without safeguardsClaude Haiku 4.5 System Card15 Oct 2025First reported | Claude Haiku 4.5 System Card15 Oct 2025First reported | |
| Single-turn violative requestsHarmless response rateCondition: no extended thinkingClaude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | Claude Haiku 4.5 System Card15 Oct 2025Restated: compare with the earlier value | |
| Malicious agentic codingSafety scoreCondition: without safeguardsClaude 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 | |
| Malicious Claude Code useRefusal rate, malicious requestsCondition: without safeguardsClaude 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 | |
| Malicious computer useRefusal rateCondition: without safeguardsClaude 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 | |
| Higher-difficulty benign requestsOver-refusal rateCondition: overall across thinking modesClaude Opus 4.6 System CardFeb 2026First reported | Claude Opus 4.6 System CardFeb 2026First reported | |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesClaude Opus 4.6 System CardFeb 2026Restated: compare with the earlier value | Claude Opus 4.6 System CardFeb 2026Restated: compare with the earlier value | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesClaude Opus 4.6 System CardFeb 2026Restated: compare with the earlier value | Claude Opus 4.6 System CardFeb 2026Restated: compare with the earlier value | |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesClaude Sonnet 4.6 System Card17 Feb 2026Restated: compare with the earlier value | Claude Sonnet 4.6 System Card17 Feb 2026Restated: compare with the earlier value | |
M9 · Prompt injection 13 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| Computer-use prompt injectionAttack prevention rateCondition: with safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Computer-use prompt injectionAttack prevention rateCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| MCP prompt injectionAttack prevention rateCondition: with safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| MCP prompt injectionAttack prevention rateCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Tool-use prompt injectionAttack prevention rateCondition: with safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| Tool-use prompt injectionAttack prevention rateCondition: without safeguards | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| From other documents | ||
| Coding prompt injection (adaptive attacker)Attack success rateCondition: extended thinking; without safeguards; 1 attemptClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Coding prompt injection (adaptive attacker)Attack success rateCondition: extended thinking; without safeguards; 200 attemptsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Coding prompt injection (adaptive attacker)Attack success rateCondition: no extended thinking; without safeguards; 1 attemptClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Coding prompt injection (adaptive attacker)Attack success rateCondition: no extended thinking; without safeguards; 200 attemptsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Computer use prompt injection (adaptive attacker)Attack success rateCondition: extended thinking; with safeguards; 200 attemptsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Computer use prompt injection (adaptive attacker)Attack success rateCondition: extended thinking; without safeguards; 1 attemptClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
| Computer use prompt injection (adaptive attacker)Attack success rateCondition: extended thinking; without safeguards; 200 attemptsClaude Opus 4.5 System Card24 Nov 2025First reported | Claude Opus 4.5 System Card24 Nov 2025First reported | |
M10 · Dangerous capabilities and risk determinations 2 values
| Evaluation and metric | Value | Document |
|---|---|---|
| From its own documentClaude Sonnet 4.5 System Card · 29 Sep 2025 | ||
| CybenchSuccess rate, pass@30Condition: 37 of 40 challenges | Claude Sonnet 4.5 System Card29 Sep 2025 | |
| RSP deployment standardASL standard deployed under | Claude Sonnet 4.5 System Card29 Sep 2025 | |
Restated in later documents
A later document reported values about Claude Sonnet 4.5 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 |
|---|---|
| M2 · Reward hacking | |
| Impossible tasksClassifier hack rateCondition: no anti-hack prompt | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Haiku 4.5 System Card15 Oct 2025No reason stated |
| M7 · Harmful compliance and over-refusal | |
| Malicious agentic codingSafety scoreCondition: without safeguards | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Haiku 4.5 System Card15 Oct 2025No reason stated |
| Malicious agentic codingSafety scoreCondition: without safeguards | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Opus 4.5 System Card24 Nov 2025Reason stated: metric renamed to refusal rate |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modesLater condition: overall across thinking modes; all languages | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Opus 4.5 System Card24 Nov 2025Reason stated: all-language totals instead of English only |
| Single-turn benign requestsOver-refusal rateCondition: overall across thinking modes | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Opus 4.6 System CardFeb 2026No reason stated |
| Single-turn violative requestsHarmless response rateCondition: no extended thinking | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Haiku 4.5 System Card15 Oct 2025No reason stated |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modesLater condition: overall across thinking modes; all languages | |
| Claude Sonnet 4.5 System Card29 Sep 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 Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Opus 4.6 System CardFeb 2026No reason stated |
| Single-turn violative requestsHarmless response rateCondition: overall across thinking modes | |
| Claude Sonnet 4.5 System Card29 Sep 2025 · its own document | Claude Sonnet 4.6 System Card17 Feb 2026No reason stated |
| Malicious Claude Code useRefusal rate, malicious requestsCondition: without safeguards | |
| Claude Haiku 4.5 System Card15 Oct 2025 · first reported | Claude Opus 4.5 System Card24 Nov 2025No reason stated |
Risk determinations
The developer's formal decisions about Claude Sonnet 4.5 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 Sonnet 4.5 System Card · 29 Sep 2025 | Responsible Scaling Policy Claude Sonnet 4.5 System Card · 29 Sep 2025 |