MatFlowBench evaluates how reliably and efficiently LLM agents carry out the materials science workflows of computational and experimental scientists. Agents run multi-step calculations, request experimental measurements, and interpret the results to reach scientific conclusions.
Four models clear a 40% pass rate. The other six stay under 30%.
MatFlowBench leaderboard: Total
#
Model
Harness
Pass rate
Rollouts passed
Pass@1
Tasks solved
1
GPT-6 AstraOpenAI
Codex
60.8%
79 / 130
60.0%
34 / 45
2
Claude Opus 5.5Anthropic
Claude Code
53.8%
70 / 130
56.7%
30 / 45
3
Claude Sonnet 5.5Anthropic
Claude Code
47.7%
62 / 130
50.0%
32 / 45
4
GPT-6.1 SolOpenAI
Codex
44.6%
58 / 130
45.0%
30 / 45
5
Grok 4.7xAI
Terminus 2
26.2%
34 / 130
22.8%
17 / 45
6
Gemini 3.8 FlashGoogle
Terminus 2
25.4%
33 / 130
18.9%
14 / 45
7
Kimi K3Moonshot AI
Terminus 2
23.8%
31 / 130
22.2%
16 / 45
8
Tencent HY4 PreviewTencent
Terminus 2
22.3%
29 / 130
20.0%
16 / 45
9
Muse Spark 1.3Meta
Terminus 2
20.0%
26 / 130
16.7%
15 / 45
10
Qwen3.8-27BAlibaba
Terminus 2
11.5%
15 / 130
8.3%
9 / 45
Total: 45 tasks, all rollouts. Every model ran at high reasoning effort. Results from October 2026.
MatFlowBench leaderboard: Computational
#
Model
Harness
Pass rate
Rollouts passed
Tasks solved
1
Claude Opus 5.5Anthropic
Claude Code
64.0%
32 / 50
17 / 25
2
GPT-6 AstraOpenAI
Codex
58.0%
29 / 50
18 / 25
3
Claude Sonnet 5.5Anthropic
Claude Code
56.0%
28 / 50
17 / 25
4
GPT-6.1 SolOpenAI
Codex
46.0%
23 / 50
17 / 25
5
Kimi K3Moonshot AI
Terminus 2
18.0%
9 / 50
7 / 25
6
Grok 4.7xAI
Terminus 2
14.0%
7 / 50
6 / 25
6
Tencent HY4 PreviewTencent
Terminus 2
14.0%
7 / 50
5 / 25
8
Muse Spark 1.3Meta
Terminus 2
8.0%
4 / 50
3 / 25
9
Gemini 3.8 FlashGoogle
Terminus 2
2.0%
1 / 50
1 / 25
10
Qwen3.8-27BAlibaba
Terminus 2
0.0%
0 / 50
0 / 25
Computational: 25 tasks × 2 rollouts per model. Every model ran at high reasoning effort. Results from October 2026.
MatFlowBench leaderboard: Experimental
#
Model
Harness
Pass rate
Rollouts passed
Tasks solved
1
GPT-6 AstraOpenAI
Codex
62.5%
50 / 80
16 / 20
2
Claude Opus 5.5Anthropic
Claude Code
47.5%
38 / 80
13 / 20
3
GPT-6.1 SolOpenAI
Codex
43.8%
35 / 80
13 / 20
4
Claude Sonnet 5.5Anthropic
Claude Code
42.5%
34 / 80
15 / 20
5
Gemini 3.8 FlashGoogle
Terminus 2
40.0%
32 / 80
13 / 20
6
Grok 4.7xAI
Terminus 2
33.8%
27 / 80
11 / 20
7
Muse Spark 1.3Meta
Terminus 2
27.5%
22 / 80
12 / 20
7
Tencent HY4 PreviewTencent
Terminus 2
27.5%
22 / 80
11 / 20
7
Kimi K3Moonshot AI
Terminus 2
27.5%
22 / 80
9 / 20
10
Qwen3.8-27BAlibaba
Terminus 2
18.8%
15 / 80
9 / 20
Experimental: 20 tasks × 4 rollouts per model. Every model ran at high reasoning effort. Results from October 2026.
02 / CostPareto frontier by track
The most expensive model is not the most accurate.
Pareto frontierOn the frontierOther models
Computational: 25 tasks × 2 rollouts per model. Cost is model API spend plus estimated compute, averaged per rollout.
Pareto frontierOn the frontierOther models
Experimental: 20 tasks × 4 rollouts per model. Cost is model API spend plus estimated compute, averaged per rollout.
03 / The constructWhat a successful task establishes
Completing a research workflow.
MatFlowBench measures whether an LLM agent can complete a specified materials research task using the available tools and data, within the task’s resource limits.
The verifier checks the evidence behind an answer. In DFT tasks it reads the agent’s calculation output files rather than the number the agent reports. In budgeted searches it checks which measurements the agent requested: a recommended material must have been measured, and a claim that no material qualifies must rest on measurements that rule out each candidate.
A pass means that the submitted result meets the task’s checks. It does not by itself establish new materials discovery, complete physical validation, or sound reasoning at every step.
01 Interpret the objective02 Use tools and data03 Submit the result04 Check the result
04 / The workflowsTwo evidence settings
Computational and experimental workflows.
In silico25 tasks
Computational
Agents are given a scientific goal and a prepared environment with Quantum ESPRESSO, Wannier90 and Phonopy for density functional theory (DFT) and related calculations. They plan and run the calculations themselves, much as a computational materials scientist would, and must carry the work through to the property or conclusion the task asks for.
Task families
Electronic structure and topologyLocate band crossings and determine topological properties.
Spin and anomalous Hall transportCalculate spin Hall or anomalous Hall response for a specified electronic and magnetic state.
Magnetism and spin structureDetermine magnetic onset, spin splitting, or band crossings in a specified magnetic state.
Strain and composition-driven transitionsLocate changes in electronic structure as strain, doping, or composition varies.
Strained-film propertiesRelax constrained films and calculate polarization or conduction-band properties.
Wannier model constructionBuild a model that reproduces specified energy bands and their alignment.
Lattice dynamicsCalculate selected phonon frequencies and locate an acoustic-branch minimum.
From measured data20 tasks
Experimental
Agents receive a set of target properties and access to a simulated lab, where every experiment returns real measured data. Each sample can be characterized on several instruments, and each instrument reveals a different set of properties. With a finite budget to spend, the agent decides which samples to prepare and which measurements are worth running, using what it learns to narrow the search until it finds a material that meets the requirements or can show that none does.
Task families
Optical-film selectionFind coatings and filters that meet several spectral requirements within a measurement budget.
Catalyst selectionSelect oxygen-evolution catalysts that meet activity and conditioning requirements.
Feasibility triageDetermine which target specifications a materials library can meet.
Raw instrument-data reductionConvert spectrometer and electrochemical files into corrected measurements and candidate selections.
05 / EvaluationHow a rollout is scored
What the score means.
Each rollout passes or fails. The task’s executable verifier makes that call, and the leaderboard reports how often each model passes.
01
Numerical references
Results are compared with numerical references, using tolerances set by the underlying physics.
02
Physical constraints and evidence
Other checks cover physical constraints from well-established scientific workflows. Some tasks also require calculation files or measurement logs, and budgeted searches must finish within their measurement budget.
03
Pass rate and Pass@1
Each model ran with high reasoning effort, twice per computational task and four times per experimental task. Pass rate is the share of all rollouts that passed, and the leaderboard is ranked by it. Pass@1 is the share of passing rollouts on a task, averaged so that every task counts equally.
Collinear is building RL environments on these workflows.
MatFlowBench shows where frontier agents fall short in materials research. The environments, with verified trajectories, target three gaps in these results.
01
Multi-step DFT pipelines
No model outside the top four passes more than 18% of computational rollouts.
02
Reliability across attempts
Across the 10 models, only 38% of the tasks solved at least once are solved on every attempt.
03
Cost per run
On computational tasks the most accurate model averages $8.23 a rollout. Models with lower pass rates spend up to $71.26.
MatFlowBench is a private benchmark from Collinear AI that measures whether LLM agents can carry out multi-step materials research workflows. It has 45 tasks: 25 computational tasks, in which agents run density functional theory (DFT) and related calculations with Quantum ESPRESSO, Wannier90 and Phonopy, and 20 experimental tasks, in which agents plan measurements, analyze archived instrument data and select materials.
Which model scores highest on MatFlowBench?+
In the October 2026 results, GPT-6 Astra has the highest pass rate on all 45 tasks at 60.8%, followed by Claude Opus 5.5 at 53.8% and Claude Sonnet 5.5 at 47.7%. On the computational tasks Claude Opus 5.5 leads at 64.0%, and on the experimental tasks GPT-6 Astra leads at 62.5%.
How is a task scored?+
Each rollout passes or fails, and the task’s executable verifier makes that call. For DFT tasks, the verifier reads the agent’s calculation output files rather than the number it reports. For budgeted searches, it checks which measurements the agent requested: a recommended material must have been measured, and an agent that reports that no material qualifies must have measured enough of the pool to rule each one out.
How were the models run and ranked?+
Each model ran with high reasoning effort, twice per computational task and four times per experimental task. OpenAI models ran in Codex, Anthropic models in Claude Code, and all others in Terminus 2. The leaderboard ranks models by pass rate, the share of all rollouts that passed. Pass@1 averages each task’s share of passing rollouts, so that every task counts equally. Cost is model API spend plus estimated compute, averaged per rollout.
Can I download the tasks?+
No. MatFlowBench is a private benchmark: its tasks, verifiers and model rollouts are not published.