Anthropic Claude 3.5 Sonnet v1 vs Google Gemini 3 Flash

Detailed comparison for LLMs

AnthropicGoogle

On Guardion's LLM vulnerability Benchmark, Google Gemini 3 Flash is the more secure of the two: Claude 3.5 Sonnet v1 scores 16.0% and Gemini 3 Flash scores 10.0% 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

Gemini 3 Flash is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for Anthropic Claude 3.5 Sonnet v1 vs Google Gemini 3 Flash. Green marks the safer model on each metric. Only the overall score is available for estimated models.

Overall (ASR)

Claude 3.5 Sonnet v1
16.0%
Gemini 3 Flash
10.0%

TAP Attack Method (ASR)

Claude 3.5 Sonnet v1
28.4%
Gemini 3 Flash

Crescendo Attack Method (ASR)

Claude 3.5 Sonnet v1
19.3%
Gemini 3 Flash

Zero-Shot (ASR)

Claude 3.5 Sonnet v1
0.3%
Gemini 3 Flash

Key Highlights

  • Google Gemini 3 Flash has a lower Overall (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Claude 3.5 Sonnet v1
Gemini 3 Flash
Full security profile
Anthropic Claude 3.5 Sonnet v1
Full security profile
Google Gemini 3 Flash

Frequently asked questions

Is Anthropic Claude 3.5 Sonnet v1 or Google Gemini 3 Flash more secure?

On Guardion's LLM vulnerability Benchmark, Google Gemini 3 Flash is the more secure of the two: Claude 3.5 Sonnet v1 scores 16.0% and Gemini 3 Flash scores 10.0% 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 3.5 Sonnet v1 vs Gemini 3 Flash?

Claude 3.5 Sonnet v1 has a 16.0% ASR and Gemini 3 Flash has a 10.0% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.

How were Claude 3.5 Sonnet v1 and Gemini 3 Flash 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.

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