Benchmark Almanac

Medicinal Chemistry (Anthropic)

Claude Sonnet 5.5 65.3% leads since Sep 2026 Only in system cards

Models see several real drug-discovery compounds and pick which had the highest or lowest measured ADME property. The set has 504 questions.

In-house Anthropic evaluation. The tasks are not public.

Made by Anthropic Released Sep 2026 Research science Tasks kept private Last in a system card Oct 2026 Last model added Oct 2026
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
Multiple choice
3
Models scored in lab cards
3
System cards report it, from 1 lab

Claude Sonnet 5.5 leads with 65.3%

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.

  1. 65.3 Claude Sonnet 5.5
  2. 63.5 Claude Opus 5.5
  3. 58.0 Claude Haiku 5.5
  1. 1 Claude Sonnet 5.5 65.3%
  2. 2 Claude Opus 5.5 63.5%
  3. 3 Claude Haiku 5.5 58%
#ModelScoreSettingDateSource
1 Claude Sonnet 5.5 65.3% Sep 2026 Model card
2 Claude Opus 5.5 63.5% Sep 2026 Model card
3 Claude Haiku 5.5 58% Oct 2026 Model card

2 models have held number one since its release in Sep 2026

Lab claims count from the day the card came out, independent runs from the model’s release.

Anthropic
Lab claims 2 leaders
Claude Sonnet 5.5 65.3%

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% Near the ceiling (85%) Claude Sonnet 5.5 0% 20% 40% 60% 80% 100% Near the ceiling (85%) Claude Sonnet 5.5

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.

3 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.

DateDocumentScoreAs the document writes itSection
7 Oct 2026 Claude Haiku 5.5 system card 58 Medicinal chemistry, max effort (8.13.3) Capabilities
28 Sep 2026 Claude Sonnet 5.5 system card 65.3 Medicinal Chemistry, 504 ADME questions (8.17.4, Figure 8.17.A) Capabilities
22 Sep 2026 Claude Opus 5.5 system card 63.5 Medicinal chemistry, 504 ADME questions, no tools, max effort (8.17.4) Capabilities

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