Anthropic Claude 3.5 Sonnet v1 vs xAI Grok-4 Heavy

Detailed comparison for LLMs

AnthropicxAI

On Guardion's LLM vulnerability Benchmark, Anthropic Claude 3.5 Sonnet v1 is the more secure of the two: Claude 3.5 Sonnet v1 scores 16.0% and Grok-4 Heavy scores 18.0% 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

Claude 3.5 Sonnet v1 is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for Anthropic Claude 3.5 Sonnet v1 vs xAI Grok-4 Heavy. 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%
Grok-4 Heavy
18.0%

TAP Attack Method (ASR)

Claude 3.5 Sonnet v1
28.4%
Grok-4 Heavy
100.0%

Crescendo Attack Method (ASR)

Claude 3.5 Sonnet v1
19.3%
Grok-4 Heavy
100.0%

Zero-Shot (ASR)

Claude 3.5 Sonnet v1
0.3%
Grok-4 Heavy
100.0%

Key Highlights

  • Anthropic Claude 3.5 Sonnet v1 has a lower Overall (ASR).
  • Anthropic Claude 3.5 Sonnet v1 has a lower TAP Attack Method (ASR).
  • Anthropic Claude 3.5 Sonnet v1 has a lower Crescendo Attack Method (ASR).
  • Anthropic Claude 3.5 Sonnet v1 has a lower Zero-Shot (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Claude 3.5 Sonnet v1
Grok-4 Heavy
Full security profile
Anthropic Claude 3.5 Sonnet v1
Full security profile
xAI Grok-4 Heavy

Frequently asked questions

Is Anthropic Claude 3.5 Sonnet v1 or xAI Grok-4 Heavy more secure?

On Guardion's LLM vulnerability Benchmark, Anthropic Claude 3.5 Sonnet v1 is the more secure of the two: Claude 3.5 Sonnet v1 scores 16.0% and Grok-4 Heavy scores 18.0% 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 Grok-4 Heavy?

Claude 3.5 Sonnet v1 has a 16.0% ASR and Grok-4 Heavy has a 18.0% 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 Grok-4 Heavy 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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