Vals Legal Index: Wonder Full leads, two Gemini 4 models close behind
Written by AI
Vals AI’s Legal Index weights areas of law by US law firm revenue, and the top three models are less than two percentage points apart. The top score of about 77 per cent does not show how many tasks were fully solved.
Vals AI published the Vals Legal Index, a benchmark of legal tasks, in October and updated the results on 5 November. Wonder Full leads with 77.86 per cent, followed by Gemini 4 Argon (76.72 per cent) and Gemini 4 Carbon (75.93 per cent). Vals says the order at the top is not settled.
BenchLM, a site that publishes Vals’s results, names the top-ranked model as Meta’s Muse Wonder Full. BenchLM has not run the tests itself.
Weights from law firm revenue
The index combines three benchmarks. Legal Research Bench measures legal research, HLAB-Vals-1.1 document drafting and review, and Tax Agent Bench tax law. HLAB is based on the Legal Agent Benchmark published by Harvey. Vals runs the tests on the benchmark’s unpublished test set.
The weights come from the Census Bureau’s Economic Census, which shows how US law firm revenue was split by area of law in 2022. Business and commercial law accounted for 37.5 per cent of revenue and carries a weight of 40.5 per cent in the index. Only HLAB measures real estate, labour and employment, and estates law, and only the research benchmark measures family law. About 7 per cent of revenue falls outside the index.
The index score does not show how many tasks were solved
HLAB contributes its criteria pass rate to the index: the share of a task’s grading criteria that were met. Harvey counts a task as solved only if every criterion is met. The gap is large: in HLAB, Gemini 4 Argon met 96.30 per cent of criteria but fully solved 27.08 per cent of tasks. Two language models, GPT 5.5 and Claude Sonnet 4.6, graded the answers.
The table shows the index’s top ten models, the cost per test and the share of tasks fully solved in HLAB.
| Rank | Model | Legal Index | Cost/test | HLAB: tasks solved |
|---|---|---|---|---|
| 1 | Wonder Full | 77.86% | $3.72 | 23.33% |
| 2 | Gemini 4 Argon | 76.72% | $6.82 | 27.08% |
| 3 | Gemini 4 Carbon | 75.93% | $7.20 | 17.50% |
| 4 | Wonder | 75.26% | $4.32 | 23.75% |
| 5 | GLM 5.3 | 74.58% | $2.68 | 14.58% |
| 6 | Qwen 3.8 Max 0902 | 73.90% | $4.25 | 15.42% |
| 7 | Inkling 2 Small | 73.89% | $0.56 | 21.67% |
| 8 | Grok 4.7 | 72.60% | $5.82 | 18.33% |
| 9 | Claude Opus 5.5 | 72.33% | $19.94 | 9.17% |
| 10 | MiMo V2.6 Pro | 72.14% | $0.18 | 13.75% |
Source: Vals AI, 5 November 2026. Cost is the average across the index’s three component benchmarks. The HLAB column uses a different metric from the index.
The index score does not show how often a model gets a legal task fully right. The ranking also depends on the metric: Muse Spark Open is second for tasks solved in HLAB (25.00 per cent) but 22nd in the index.
Family law is the weakest area
No model leads in every area of law. Gemini 4 Carbon is best in family and criminal law. Wonder Full leads in business and commercial law, real estate, labour and employment, and wills, estates and trusts. In family law, the models average 21 per cent.
Vals says the standard error is largest in areas that only the research benchmark measures; that benchmark has just a few dozen questions per area. The index’s standard errors are also slightly too small, Vals added. BenchLM points out that the index measures how models and agents perform on legal tasks, not actual legal work.
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