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Claude Opus 5.5

Released 22 Sep 2026$4 input, $20 output per million tokens1M contextproprietaryAlso written as anthropic/claude-opus-5-5, claude-opus-5-5

4 results on 4 of 13 boards, latest measured Sep 2026. Compare with other models

Clinical Benchmarks Index51.8Rank 10 of 1494 of 10 boardsAverage × multiplier 63.5 × 0.816 = 51.8This site’s own calculation. Working How it is computed

Results

Each line sits on its own board's scale. Tall tick: the board leader.

Clinical reasoning and knowledge

  1. HealthBench Professional
    Anthropic; adaptive max effort; Opus 4.8 grader; five trials; no tools or custom system prompt; safety classifiers and refusal fallback to Opus 5; length-adjusted; raw 77.1%
    0.656
    Rank 4 of 35Leader GPT-6 Astra (Anthropic run) 0.703
    Vendor-reported
    Measured Sep 2026

Documentation and coding

  1. MedScribe (Vals AI)
    model ID anthropic/claude-opus-5-5; temperature=1; max_output_tokens=128000; compute_effort=max
    91.43
    Rank 1 of 105Leads this board
    Official leaderboard
    Measured Sep 2026
  2. MedCode (Vals AI)
    model ID anthropic/claude-opus-5-5; compute_effort=max; temperature=1; max_output_tokens=128000
    49.80
    Rank 16 of 103Leader Claude Opus 5 63.57
    Official leaderboard
    Measured Sep 2026

EHR and workflow agents

  1. PhysicianBench
    Anthropic harness; 100 tasks; pass@1; max effort; Opus 5 rubric grader; safety classifiers enabled
    68.4
    Rank 1 of 28 here, 12 models on the boardLeads this board
    Vendor-reported
    Measured Sep 2026

Index working

The Clinical Benchmarks Index is this site's own calculation: a weighted average of the board scores times a multiplier for the boards behind it. How it is computed

  • HealthBench Professional0.65665.6×0.743Anthropic; adaptive max effort; Opus 4.8 grader; five trials; no tools or custom system prompt; safety classifiers and refusal fallback to Opus 5; length-adjusted; raw 77.1%
  • MedScribe (Vals AI)91.4391.4×0.25, near its ceilingNear its ceiling: leader 91.4, weight 0.25model ID anthropic/claude-opus-5-5; temperature=1; max_output_tokens=128000; compute_effort=max
  • MedCode (Vals AI)49.8049.8×0.911model ID anthropic/claude-opus-5-5; compute_effort=max; temperature=1; max_output_tokens=128000
  • PhysicianBench68.468.4×0.79Anthropic harness; 100 tasks; pass@1; max effort; Opus 5 rubric grader; safety classifiers enabled
Weighted average of 4 boards
63.5
Multiplier for 4 of 10 boards
× 0.816
Index
63.5 × 0.816 = 51.8

Score: the result on the board’s own 0 to 100 scale. Dot: this model; tick: the board’s leader. Weight: how much the board counts in the weighted average; bold where the board is near its ceiling and counts for less. Each result links to its quote and page; the line under it is the setting it was measured with.

Sources

The quote, page and document for each of the 4 results
  1. 4HealthBench Professional adaptive max effort 0.656
    Printed as 65.6%Vendor-reported, measured Sep 2026Configuration: Anthropic; adaptive max effort; Opus 4.8 grader; five trials; no tools or custom system prompt; safety classifiers and refusal fallback to Opus 5; length-adjusted; raw 77.1%
    Claude Opus 5.5 System Card system card, Anthropic, 22 Sep 2026. pp. 213–214, Section 8.15.2, paragraph and Figure 8.15.2.A.
    8.15.2 HealthBench Professional results length adjustment, which penalizes verbose model responses, Claude Opus 5.5 achieved a score of 65.6%.
    Every result from this document
  2. 1MedScribe (Vals AI) claude-opus-5-5 91.43
    Printed as 91.43%Official leaderboard, measured Sep 2026Configuration: model ID anthropic/claude-opus-5-5; temperature=1; max_output_tokens=128000; compute_effort=max
    Vals AI MedScribe leaderboard official leaderboard, Vals AI, 3 Sep 2026. Vals AI MedScribe leaderboard, View: All Models, Task: Overall, row 1 of 105 (Claude Opus 5.5), Accuracy column; Updated 9/29/2026. Rendered BenchmarkView table; configuration from embedded astro-island BenchmarkView props, benchmarkView.default.tasks.overall["anthropic/claude-opus-5-5"].
    1 | Claude Opus 5.5 | 91.43%±1.93 | $4/$20 | 7m22s
    Every result from this document
  3. 16MedCode (Vals AI) claude-opus-5-5 49.80
    Printed as 49.80%Official leaderboard, measured Sep 2026Configuration: model ID anthropic/claude-opus-5-5; compute_effort=max; temperature=1; max_output_tokens=128000
    Vals AI MedCode leaderboard official leaderboard, Vals AI, 29 Sep 2026. MedCode leaderboard, Overall task, All Models expanded, rank 16 of 103; Accuracy column; board Updated 9/29/2026. Rendered table row; configuration from embedded BenchmarkView props benchmarkView.default.tasks.overall["anthropic/claude-opus-5-5"].
    16 | Claude Opus 5.5 | 49.80%±2.27 | $4/$20 | 4m07s
    Every result from this document
  4. 1PhysicianBench Anthropic harness 68.4
    Printed as 68.4%Vendor-reported, measured Sep 2026Configuration: Anthropic harness; 100 tasks; pass@1; max effort; Opus 5 rubric grader; safety classifiers enabled
    Claude Sonnet 5.5 System Card system card, Anthropic, 28 Sep 2026. pp. 138–139, Section 8.15.3; PhysicianBench pass@1, Claude Opus 5.5 (max).
    PhysicianBench is a public benchmark of 100 physician tasks carried out in an EHR. At max effort, Claude Sonnet 5.5 passes 63.2% of attempts, well above Claude Sonnet 5 (37.4%), level with Claude Fable 5.1 (61.0%), about 6 points above Claude Opus 5 (57.6%) and about 5 points below Claude Opus 5.5 (68.4%).
    Every result from this document

Other Anthropic models: Claude 3.7 Sonnet, Claude Fable 5, Claude Fable 5.1, Claude Haiku 4.5, Claude Haiku 5.5, Claude Opus 4.1, Claude Opus 4.5, Claude Opus 4.6, Claude Opus 4.7, Claude Opus 4.8, Claude Opus 5, Claude Sonnet 4, Claude Sonnet 4.5, Claude Sonnet 4.6, Claude Sonnet 5, Claude Sonnet 5.5