Claude Fable 5 on HealthBench Professional

rank 1 of 9 · updated August 16, 2026

Claude Fable 5 scores 0.660 on HealthBench Professional, rank 1 of 9 evaluated models. Anthropic's top-tier model, positioned above the Opus line for the hardest reasoning work. HealthBench Professional scores models on 525 tasks drawn from real clinician conversations, graded criterion by criterion against physician-written rubrics on a 0 to 1 scale.

Result and API facts

rank	1 of 9
score	0.660
lab	Anthropic
context window	1.0M tokens
API price per 1M tokens	$10.00 in / $50.00 out
license	proprietary
released	2026-06-09

Position in the field

Claude Fable 5 leads the leaderboard, 0.055 ahead of GPT-5.6 Sol in second place. Scores on this page come from the same evaluation run, so differences between models are differences on identical tasks, not across configurations.

What does Claude Fable 5 score on HealthBench Professional?

Claude Fable 5 scores 0.660 on HealthBench Professional, which places it at rank 1 of 9 evaluated models as of August 16, 2026.

How much does Claude Fable 5 cost to run?

Claude Fable 5 is priced at $10.00 per million input tokens and $50.00 per million output tokens through Anthropic's API.

Head to head

Pairings with a dedicated comparison page are linked; every other difference is in the score-difference matrix.

Claude Fable 5 vs GPT-5.6 Sol
0.660 vs 0.605 · Claude Fable 5 by 0.055
Claude Fable 5 vs Claude Opus 5
0.660 vs 0.598 · Claude Fable 5 by 0.062
Claude Fable 5 vs Claude Sonnet 5
0.660 vs 0.578 · Claude Fable 5 by 0.082
Claude Fable 5 vs GPT-5.6 Terra
0.660 vs 0.577 · Claude Fable 5 by 0.083
Claude Fable 5 vs Claude Opus 4.8
0.660 vs 0.558 · Claude Fable 5 by 0.102
Claude Fable 5 vs GPT-5.6 Luna
0.660 vs 0.557 · Claude Fable 5 by 0.103
Claude Fable 5 vs GPT-5.5 Instant
0.660 vs 0.384 · Claude Fable 5 by 0.276
Claude Fable 5 vs MAI-Thinking-1
0.660 vs 0.350 · Claude Fable 5 by 0.310

How tasks are selected and graded is on the methodology page. The full ranking is on the leaderboard.