← Claude Opus 4.8 · API · High effort (default)
Evidenceacceptedthird_party_leaderboard
Chatbot Arena / LMArena human preference
Chatbot Arena mirror (openlm.ai) — Claude Opus 4.8 Thinking
ev_2026_07_opus48_arena
Result
1506
Confidence B
- Tested
- 2026-07-11
- Runs
- 1
Configuration
How it was measured
- Exact model
- claude-opus-4-8
- Reasoning
- high
- Agent harness
- none
- Tool access
- chat surface
- Prompting
- anonymous pairwise battles
PRIMARY CHA — Arena preference Elo.
Caveats
Known limitations
- Style/length biases; confirm LMArena at freeze.
Weighting
Evidence weight factors
The engine weights each evidence row by these factors (0–1) when fusing scores — higher is more trusted.
relevance0.90
quality0.85
recency1.00
health0.85
comparability0.75
reliability0.80
Benchmark
Chatbot Arena / LMArena human preference
Blind pairwise human preference battles aggregated into Elo ratings for chat quality, style, and helpfulness under real user prompts.
Benchmark source →