Claude Opus 5.5 (Adaptive Reasoning, Medium Effort, Default Fallback) appeared in artificial_analysis
model_release · 2026-09-17T00:00:00.000Z
Source ↗Anthropic · active
anthropic/claude-opus-5-5-medium
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Bounded, independently loaded observations and the stories behind them.
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Collector releases and news-derived announcements, clearly labeled by confirmation state.
model_release · 2026-09-17T00:00:00.000Z
Source ↗Model record
Sourced per-million-token rates over time.
2026-09-22T21:41:06.537Z · artificial_analysis
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Stories and source evidence attached to model announcements.
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Adoption observations in their original metric context.
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Human-readable benchmark results with rank and score.