Claude Opus 5.5 (Max)
An evaluated model label, preserved from the source. Use the evidence below to understand what was measured and what remains unknown.
Source CI: 1793.6 to 1820.3
3,140 votes
Published 2026-10-23
Arena web development preference rating (overall). Distinct from repository issue resolution or general coding accuracy.
95% CI: 0.1839 to 0.2315
1,751,647 observations · 12,057 sessions
Published 2026-10-23
Arena agent IPS score (overall). Interpret within the source methodology; not interchangeable with text or web development ratings.
Evaluation record
- Source
- arena
- Publisher / namespace
- anthropic
- Prompt mode
- Not supplied
- Source-reported parameters
- Not provided
- Model release date
- Not provided
- Evaluation date
- Not supplied per model
- Source updated
- 22 Oct 2026
- Source revision
- 9761a3ce414bac9ebac5a7742f67f230be809df4
- Reasoning effort / harness
- Not supplied per model in this source
- Confidence intervals
- Shown with each measurement above; overlapping intervals do not establish superiority
- Model license / context limit
- Not verified in this dataset
Price, speed & practical use
Verified pricing is not included in this source. We do not infer current API pricing from historical model names.
Output speed: not measured in this dataset.
Source ratings describe specific evaluations and configurations; they do not establish reliability for every application or agent workflow. Validate candidates on your own workload.
Source: Arena / lmarena-ai leaderboard dataset, CC BY 4.0. Filtered to the latest overall boards and normalized by BuildnScale; evaluations were not rerun. No endorsement implied.
Published evidence. Clear sources. No sponsored rank placement.
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