HealthBench Professional

How each maker reported it

• Claude Sonnet 5.5 Table 8.1.A, p.109

  Claude results use adaptive thinking at max effort with default sampling, averaged over five trials. Competitor figures come from the developers' own published system cards or leaderboards.

• Claude Opus 5.5 Table 8.1.A, p.174

  Claude results use adaptive thinking at max effort, averaged over five trials (Terminal-Bench 4.0 at xhigh). Competitor figures come from the developers' own published results.

• GPT-6 Astra Launch post (openai.com/index/gpt-6-astra); system card §6, §10.1; GPT-6.1 Sol addendum §5, §9

  Coding and reasoning rows come from the GPT-6 Astra launch post (3 Sep 2026); OpenAI's own comparison table, settings as published there. The system card reports safety and Preparedness evaluations, not general capability benchmarks. Cyber and bio scores are at maximum reasoning effort; bio scores are refusal-adjusted. HealthBench scores are length-adjusted. GPT-6.1 Sol and some GPT-5.6 Sol values come from the GPT-6.1 Sol addendum (29 Sep 2026).

• GPT-6.1 Sol §5, §9

  The addendum reports safety and Preparedness evaluations, not general capability benchmarks. Cyber and bio scores are at maximum reasoning effort; bio scores are refusal-adjusted. HealthBench scores are length-adjusted.

• Claude Fable 5.1 Table 8.1.A, p.167

  Fable 5.1 and Mythos 5.1 share weights, so column 0 covers both (likewise Fable 5 / Mythos 5). Claude results use adaptive thinking at max effort, averaged over five trials. Terminal-Bench 4.0 values are from §8.6, p.171 (Mythos 5.1: 60.9%; GPT-5.6 Sol from the public leaderboard). Competitor figures come from the developers' own published results or leaderboards.

• GPT-6 Luna Appendix A, p.120–154; GPT-6.1 Sol addendum Table 9

  The card reports safety and Preparedness evaluations, not general capability benchmarks. Cyber and bio scores are at maximum reasoning effort; HealthBench scores are length-adjusted. MentalHealthBench comes from the GPT-6.1 Sol addendum.

• Claude Opus 5 Table 8.1.A, p.148–149

  Claude Opus 5 results use adaptive thinking at max effort, averaged over five trials (ARC-AGI-3 at high effort). GPT-5.6 Sol's FrontierBench figure uses Codex and its ARC-AGI-1 figure is at xhigh. The Fable 5 HealthBench Professional figure carries a footnote reading "Mythos 5". Competitor figures come from the developers' own published results or leaderboards.

• Grok 4.7 §2–6, p.5–16

  Grok 4.7 at xhigh effort except DeepSWE, SWE-Marathon, CADGenBench and CyberGym (high). Grok 4.6 at high except FrontierSWE, EEBench and HealthBench (xhigh). Most results come from third-party evaluators, each running its own harness; competitor results use max effort (CADGenBench GPT-5.6 Sol at xhigh). CyberGym is run without production safeguards.