Backed byY Combinator

Physician-graded clinical data for frontier AI.

Practicing physicians write net-new clinical cases and grade how a model works through them. You get faithful signal for medical reasoning, not desk labeling, simulated patients, or a model grading itself.

The data

A catalog built to fix what today's benchmarks can't

Six physician-produced data tracks, each positioned against the gold-standard benchmark it improves on.

Text · interactiveFeatured

Interactive clinical cases + trajectory grading

Physician-authored sequential patient cases with a hidden ground-truth state and faithful transitions, plus physician grading of a model's whole decision trajectory.

AgentClinicCRAFT-MDSDBench / MAI-DxOMedAgentBench
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Text

Physician rubric-graded conversations

Net-new consented multi-turn clinical conversations graded by physicians against adjudicated rubrics for correctness, completeness, safety, and calibration.

HealthBenchHealthBench HardMedHELM
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Text

Clinical reasoning + physician reasoning traces

Vignettes, differentials, and management plans with step-wise physician reasoning traces. This is supervised signal for medical verifiers and process-reward models.

MedQA (USMLE)MedMCQAPubMedQAMedXpertQA
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Image + text

Multimodal diagnostic imaging

Physician diagnostic grounding and reasoning across radiology, dermatology, pathology, ECG, and clinical photographs.

VQA-RADPathVQAMIMIC-CXRGMAI-MMBench
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Video

Egocentric procedural / surgical video

Consented first-person procedural video with dense hierarchical expert annotation (procedure → phase → step → action), operator rationale, and an error taxonomy.

Cholec80Ego-Exo4DSurgVLP
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Text / multimodal

Safety, red-teaming & hallucination

Physician-authored adversarial cases with a severity-graded harm/error taxonomy that separates reasoning-process failures from factual and safety ones.

Med-HALTMedHELM (safety)HealthBench (safety)
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The problem

Most clinical evals are static, contaminated, and model-judged

Each of those is a measured failure mode, not an opinion.

→ 51.6%

GPT-4 falls from ~90% on the MedQA exam to 51.6% once the same medicine is played out as a sequential encounter; Llama-2-70B drops from ~60% to 4.5%.

AgentClinic, npj Digital Medicine, 2026

AUC 0.49-0.66

LLM judges separate complete from incomplete clinical answers only marginally above chance. Even when they agree with a clinician, they cite the same reasoning just 24.6% of the time.

Independent evaluations of LLM clinical graders, 2025 to 2026

< 32%

No frontier model scored above 32% on HealthBench Hard at release, a benchmark that took 262 physicians writing 48,562 rubric criteria to build.

HealthBench, OpenAI, 2025

How it works

Produce-and-grade, not labeling

The state and the grades both come from clinicians, so the signal is faithful and hard to game.

01

Physicians author

Practicing physicians build each case as an interactive text (or multimodal) environment with a hidden ground-truth state and faithful transitions for every clinically sensible action.

02

Models act

The model takes a history, orders and reads tests, revises the differential, and manages the patient over time. Each fact appears only in response to an action.

03

Physicians grade the trajectory

The same physicians grade the whole decision process against an adjudicated rubric: accuracy, calibration under uncertainty, and safety at each step.

04

Delivered in your formats

You get it as an evaluation, and the graded trajectories double as training signal for SFT, preference/RLHF, and process-reward or verifier training.

Why physicians, not simulation

Fidelity is the whole game

Automated patient simulators and model judges don't reach the bar the benchmarks' own authors set. Physicians who author the case and grade the trajectory do. A general labeling workforce doesn't.

Consent & ethics

Physicians write net-new cases. Nothing comes from identifiable records, so the content carries no patient-level privacy burden.

Uncontaminated

Benchmarks built from published case reports can already sit in a model's training data. Net-new cases cannot.

Compliance-ready

If you later fold in real cases, the usual consent, ethics approval, de-identification, and HIPAA/GDPR-aware licensing apply.

See a case before you commit

Book a demo and we'll build one case end to end: the environment, the hidden ground-truth state, the grading rubric, and a graded model rollout, in your evaluation format, at no cost. Your team judges the fidelity first.