Anthropic Claude Sonnet 4.5 vs Anthropic Claude Opus 4.5
Detailed comparison for LLMs
On Guardion's LLM vulnerability Benchmark, Anthropic Claude Opus 4.5 is the more secure of the two: Claude Sonnet 4.5 scores 4.2% and Claude Opus 4.5 scores 3.4% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.
Head-to-Head Overview
Claude Opus 4.5 is the overall winner in this comparison!
Attack Success Rate (lower is safer)
ASR for Anthropic Claude Sonnet 4.5 vs Anthropic Claude Opus 4.5. Green marks the safer model on each metric. Only the overall score is available for estimated models.
Overall (ASR)
TAP Attack Method (ASR)
Crescendo Attack Method (ASR)
Zero-Shot (ASR)
Key Highlights
- Anthropic Claude Opus 4.5 has a lower Overall (ASR).
Security Profile
Outward is better on every axis.
Frequently asked questions
Is Anthropic Claude Sonnet 4.5 or Anthropic Claude Opus 4.5 more secure?
On Guardion's LLM vulnerability Benchmark, Anthropic Claude Opus 4.5 is the more secure of the two: Claude Sonnet 4.5 scores 4.2% and Claude Opus 4.5 scores 3.4% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.
What is the attack success rate (ASR) of Claude Sonnet 4.5 vs Claude Opus 4.5?
Claude Sonnet 4.5 has a 4.2% ASR and Claude Opus 4.5 has a 3.4% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.
How were Claude Sonnet 4.5 and Claude Opus 4.5 tested?
Both were red-teamed with the HarmBench framework across zero-shot, TAP (Tree of Attacks with Pruning), and Crescendo multi-turn attacks, scored by Attack Success Rate.