Protocols (Anthropic life sciences)
Models find and fix errors in molecular biology protocols and answer practical questions about applying real laboratory protocols.
Reported as two variants, Troubleshooting and Understanding (V2), with no overall score. Benchling built the Understanding set. From the Claude Opus 5.5 system card it is one of three evaluations Anthropic uses for CB-1 capability, with VCT and BioMysteryBench, replacing the Long-Form Virology Tasks.
- Level
- Expert Specialists with years of training, often over hours of work
- Scored
- Checked automatically A program checks the result against an answer key, unit tests or the expected final state.
- Answers
- Short answer A number, word or short string matched to a key.
Claude Sonnet 5 leads with 62% among models released by Jun 2026
Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.
The newest model with a score here came out in Jun 2026, and nobody has reported a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- GPT-6 Astra
- Claude Opus 5.5
- GPT-6.1 Terra
- GPT-6.1 Sol
- and 15 more
- 1 Claude Sonnet 5 62%
- 2 Claude Opus 4.8 59.6%
- 3 Claude Opus 4.7 51.8%
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Claude Sonnet 5 | 62% | Jun 2026 | Model card | |
| 2 | Claude Opus 4.8 | 59.6% | May 2026 | Model card | |
| 3 | Claude Opus 4.7 | 51.8% | Apr 2026 | Model card |
Number one over time
Lab claims count from the day the card came out, independent runs from the model’s release.
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Labs report it only in system cards
We read the headline results of 479 launch posts from 51 labs, and none of them list this benchmark. Some system cards do, below.
7 system cards report it, from 1 lab
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| 7 Oct 2026 | Claude Haiku 5.5 system card | Protocols, Troubleshooting 58.0 and Understanding (V2) 64.1, no overall (8.13.6, CB-1 evaluation in 2.2.2) | Bio and chem risk | |
| 28 Sep 2026 | Claude Sonnet 5.5 system card | Protocols, Troubleshooting 67.3% and Understanding (V2) 66.6%, no overall (2.2.2 and 8.17.8, Figure 8.17.A) | Bio and chem risk | |
| 22 Sep 2026 | Claude Opus 5.5 system card | Protocols, Troubleshooting 73.7% and Understanding (V2) 69.0%, no overall, final model (2.2.3.1 and 8.17.8) | Bio and chem risk | |
| 24 Jul 2026 | Claude Opus 5 system card | Protocols, Troubleshooting 61.1% and Understanding 78.4%, no overall (8.17.6) | Capabilities | |
| 30 Jun 2026 | Claude Sonnet 5 system card | 62 | Protocol troubleshooting, with web search, score 0.62. Only the Troubleshooting variant is reported (8.14.6, Figure 8.14.6.A) | Capabilities |
| 28 May 2026 | Claude Opus 4.8 system card | 59.6 | Protocol troubleshooting with bash and web search tools. Only the Troubleshooting part is reported (8.16.7) | Capabilities |
| 16 Apr 2026 | Claude Opus 4.7 system card | 51.8 | Protocol troubleshooting with bash and web search tools. Only the troubleshooting variant is reported (8.13.6) | Capabilities |
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