# Protein mutation attribution (Protein Mutation Attribution)

> Anthropic's life-sciences evaluation of whether a model can attribute the effects of protein mutations.

Canonical page: https://benchlm.ai/benchmarks/proteinmutationattribution

- Category: [Knowledge](/knowledge)
- Last updated: November 11, 2026

## About Protein Mutation Attribution

- Year: 2026
- Tasks: Protein mutation questions
- Format: Accuracy
- Difficulty: Protein understanding
- Paper: [Claude Fable 5.2 and Claude Mythos 5.2 system card](https://assets.claude.com/27d60918d218125e7504bc7354c4b4626ec56b11.pdf)

Reported in the Claude Fable 5.2 and Mythos 5.2 system card for Mythos 5.2 with biology safeguards off, against Claude Opus 5.5 and Mythos 5.1. Internal, so display-only.

Protein Mutation Attribution is currently displayed on BenchLM for reference, but it is excluded from the weighted scoring formula.

## Leaderboard (3 models)

| Rank | Model | Creator | Score |
|------|-------|---------|-------|
| 1 | [Claude Mythos 5.2](/models/claude-mythos-5-2) | Anthropic | 51.5% |
| 2 | [Claude Opus 5.5](/models/claude-opus-5-5) | Anthropic | 49.5% |
| 3 | [Claude Mythos 5.1](/models/claude-mythos-5-1) | Anthropic | 48.0% |

## FAQ

### What does Protein Mutation Attribution measure?

Anthropic's life-sciences evaluation of whether a model can attribute the effects of protein mutations.

### Which model scores highest on Protein Mutation Attribution?

Claude Mythos 5.2 by Anthropic currently leads with a score of 51.5% on Protein Mutation Attribution.

### How many models are evaluated on Protein Mutation Attribution?

3 AI models have published results on Protein Mutation Attribution in the BenchLM catalog.

### Does Protein Mutation Attribution affect BenchLM's overall score?

Not directly. Protein Mutation Attribution is still displayed on BenchLM for reference, but it is excluded from the weighted scoring formula.

## Compare Top Models on Protein Mutation Attribution

- [Claude Mythos 5.2 vs Claude Opus 5.5](/compare/claude-mythos-5-2-vs-claude-opus-5-5)
- [Claude Opus 5.5 vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-claude-opus-5-5)