Benchmark Almanac

FATE-X

Leanstral 1.5 34% leads since July 2026
Fading

Provers write Lean proofs for 100 algebra problems at or beyond PhD qualifying exam level, some beyond what Mathlib covers. The Lean compiler checks each proof.

Part of the FATE (Formal Algebra Theorem Evaluation) series with FATE-H. Seed-Prover 1.5 reports 33%.

Released
November 2025
Kind
Formal proofs
Level
Research frontier
Scored
Checked automatically
Answers
Written proof
Last in a launch post
July 2026, dropped before it saturated
Last model added
July 2026

In the authors’ words

Recent advances in large language models (LLMs) have demonstrated impressive capabilities in formal theorem proving, particularly on contest-based mathematical benchmarks like the IMO. However, these contests do not reflect the depth, breadth, and abstraction of modern mathematical research. To bridge this gap, we introduce FATE (Formal Algebra Theorem Evaluation), a new benchmark series in formal algebra designed to chart a course toward advanced mathematical reasoning. We present two new components, FATE-H and FATE-X, each with 100 problems in abstract and commutative algebra. The FATE series spans a difficulty spectrum from undergraduate exercises to problems exceeding PhD qualifying exams. Notably, FATE-X is the first formal benchmark to surpass both PhD-level exam difficulty and the coverage of the Mathlib library. Our evaluations of state-of-the-art LLM provers on this new benchmark reveal a stark performance gap compared to contest math: the best model achieves only 3% (pass@64) accuracy on FATE-H and 0% on FATE-X. Our two-stage evaluation reveals that models' natural-language reasoning is notably more accurate than their ability to formalize this reasoning. We systematically classify the common errors that arise during this formalization process. Furthermore, a comparative study shows that a specialized prover can exhibit less effective reflection than general-purpose models, reducing its accuracy at the natural-language stage. We believe FATE provides a robust and challenging benchmark that establishes essential checkpoints on the path toward research-level formal mathematical reasoning.

Abstract of FATE: A Formal Benchmark Series for Frontier Algebra of Multiple Difficulty Levels (arXiv:2511.02872, CC0)
2
Models scored in lab cards
2
Launch posts list it, from 2 labs
1
System card reports it, from 1 lab

Leanstral 1.5 leads with 34%

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

  1. 1 Leanstral 1.5 34%
  2. 2 Seed-Prover 1.5 33%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 Leanstral 1.5 34% Jul 2026 Lab model card
2 Seed-Prover 1.5 33% Dec 2025 Lab model card

2 models have held number one in labs’ own numbers since its release in November 2025

Lab claims count from the day the card came out, independent runs from the model’s release.

ByteDance Seed Mistral AI
Lab claims Not tested since Jul 2026

Source: Labs’ model cards

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

Reported by the lab in its model card Best so far
0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) Leanstral 1.5 Seed-Prover 1.5 0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) Leanstral 1.5

Source: Labs’ model cards

Labs headline it less often now, last in July 2026

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

ByteDance Seed
Mistral AI
DateLaunch postScoreAs the post writes it
Jul 2, 2026 Leanstral 1.5 34 FATE-X 34%
Dec 19, 2025 Seed-Prover 1.5 33 Fate-X

One system card reports it

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
Jul 2, 2026 Leanstral 1.5 technical report 34 FATE-X pass@8, 27 at pass@2 (Table 2) Capabilities

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