Benchmark Almanac

MLE-bench 30

GPT-5.5 36.7% leads since April 2026
Only in system cards

Agents train models for 30 of MLE-bench's Kaggle-style competitions. The score is the share of runs that earn a bronze medal or better.

OpenAI's system cards report this subset, and Meta reports a 30-task subset in its preparedness reports. It has no public leaderboard.

Made by
OpenAI
Released
August 2025
Kind
Machine learning engineering
Level
Expert
Scored
Checked automatically
Answers
Agent task
Tasks
All public
Strongest model tested
GPT-5.5 #20 on the capability index
Last in a system card
June 2026
Last model added
June 2026

In the authors’ words

We introduce MLE-bench, a benchmark for measuring how well AI agents perform at machine learning engineering. To this end, we curate 75 ML engineering-related competitions from Kaggle, creating a diverse set of challenging tasks that test real-world ML engineering skills such as training models, preparing datasets, and running experiments. We establish human baselines for each competition using Kaggle's publicly available leaderboards. We use open-source agent scaffolds to evaluate several frontier language models on our benchmark, finding that the best-performing setup–OpenAI's o1-preview with AIDE scaffolding–achieves at least the level of a Kaggle bronze medal in 16.9% of competitions. In addition to our main results, we investigate various forms of resource scaling for AI agents and the impact of contamination from pre-training. We open-source our benchmark code (github.com/openai/mle-bench/) to facilitate future research in understanding the ML engineering capabilities of AI agents.

Abstract of MLE-bench: Evaluating Machine Learning Agents on Machine Learning Engineering (arXiv:2410.07095, CC0)
8
Models scored in lab cards
8
System cards report it, from 2 labs

GPT-5.5 leads with 36.7% among models released by April 2026

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.

The newest model with a score here came out in April 2026, and nobody has reported a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:

  1. 1 GPT-5.5 36.7%
  2. 2 GPT-5.4 23.3%
  3. 3 GPT-5.1-Codex-Max 17%
  4. 4 GPT-5.2 16%
  5. 5 Muse Spark 15.8%
  6. 6 GPT-5.2 Codex 10%
  7. 7 GPT-5 8.00%
  8. 8 GPT-5 mini 3.00%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 GPT-5.5 36.7% Apr 2026 Lab model card
2 GPT-5.4 23.3% Mar 2026 Lab model card
3 GPT-5.1-Codex-Max 17% Nov 2025 Lab model card
4 GPT-5.2 16% Dec 2025 Lab model card
5 Muse Spark 15.8% Jun 2026 Lab model card
6 GPT-5.2 Codex 10% Dec 2025 Lab model card
7 GPT-5 8.00% Aug 2025 Lab model card
8 GPT-5 mini 3.00% Aug 2025 Lab model card

4 models have held number one in labs’ own numbers since its release in August 2025

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

OpenAI
Lab claims Not tested since Jun 2026
GPT-5.5 36.7%

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%) GPT-5.5 GPT-5.4 GPT-5.1-Codex-Max GPT-5 0% 20% 40% 60% 80% 100% 2026 Near the ceiling (85%) GPT-5.5 GPT-5.4

Source: Labs’ model cards

Labs report it only in system cards

We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.

8 system cards report it, from 2 labs

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
Jun 12, 2026 Muse Spark system card 15.8 MLE-Bench any medal rate, 30-task subset, 24 hours (Table 1, Table 11) AI R&D risk
Apr 23, 2026 GPT-5.5 system card 36.7 MLE-Bench-30 (30-competition subset), bronze or better, pass@1, printed chart label (Figure 19, 9.1.3.2) AI R&D risk
Mar 5, 2026 GPT-5.4 system card 23.3 MLE-Bench (30-competition subset), pass@1, printed chart label (Figure 16, 5.1.3.2) AI R&D risk
Dec 18, 2025 GPT-5.2 Codex system card addendum 10 MLE-Bench-30 (30-competition subset), bronze pass@1, printed chart label (Figure 10, 5.1.3.2) AI R&D risk
Dec 11, 2025 GPT-5.2 system card addendum 16 MLE-Bench-30, 30-competition subset, bronze pass@1, no browsing, printed chart label (Figure 14) AI R&D risk
Nov 18, 2025 GPT-5.1-Codex-Max system card 17 MLE-Bench-30 (30-competition subset), bronze pass@1, printed chart label (Figure 12, 5.1.3.3) AI R&D risk
Aug 7, 2025 GPT-5 system card 8 MLE-Bench-30, bronze pass@1, no browsing launch candidate (Figure 23) AI R&D risk
Aug 7, 2025 GPT-5 mini system card 3 MLE-Bench-30, bronze pass@1, gpt-5-thinking-mini launch candidate (Figure 23) AI R&D risk

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