Best Factuality AI Models in 2026

This reporting page is intentionally narrow. It focuses on currently tracked sourced factuality signals such as SimpleQA, HLE without tools, and multimodal factuality. It is a reporting page, not a mature weighted category.

This page ranks models using only sourced factuality benchmarks in the reporting family.

According to BenchLM.ai, Claude Mythos Preview leads this ranking with a score of 56.8, followed by Gemini 3.1 Pro (45.4) and Muse Spark (42.8). There is a significant gap between the leading models and the rest of the field.

The best open-weight option is Gemma 4 31B (ranked #10 with a score of 19.5). While proprietary models lead, open-weight options are within striking distance for teams willing to trade a few points of performance for full model control.

This ranking is based on provisional overall weighted scores across BenchLM.ai's scoring formula tracked by BenchLM.ai. For detailed model profiles, click any model name below. To compare two specific models head-to-head, use the "vs #" links.

Full Rankings (11 models)

Claude Mythos Preview
Anthropic·Proprietary·1M

56.8

sourced avg

Gemini 3.1 Pro
Google·Proprietary·1M

45.4

sourced avg

Muse Spark
Meta·Proprietary·262K

42.8

sourced avg

4
GPT-5.4 Pro
OpenAI·Proprietary·1.05M

42.7

sourced avg

5
Claude Opus 4.6
Anthropic·Proprietary·1M

40

sourced avg

6
GPT-5.4
OpenAI·Proprietary·1.05M

39.8

sourced avg

7
Grok 4.20
xAI·Proprietary·2M

31.6

sourced avg

8
GPT-5.4 mini
OpenAI·Proprietary·400K

28.2

sourced avg

9
GPT-5.4 nano
OpenAI·Proprietary·400K

24.3

sourced avg

10
Gemma 4 31B
Google·Open Weight·256K

19.5

sourced avg

11
Gemma 4 26B A4B
Google·Open Weight·256K

8.7

sourced avg

Key Takeaways

The top model on this sourced reporting-family slice is Claude Mythos Preview by Anthropic with an average of 56.8.

The best open-weight model is Gemma 4 31B at position #10.

11 models are listed with sourced benchmark coverage in this reporting family.

Last updated: April 8, 2026

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