💥Today we release InferenceBench, our next benchmark after PostTrainBench that measures progress on AI R&D automation.
AI R&D automation will very likely unfold gradually, starting from “boring” tasks like inference speed optimization that are very easily verifiable (accuracy + inference time). We show a rather negative result for current frontier agents. They are not good at system-level engineering and managing complex dependencies. They do show non-trivial performance, but they fail compared to a simple baseline: hyperparameter tuning of vLLM/SGLang hyperparameters.
Importantly, InferenceBench tests *open-ended* inference optimization capabilities. This is different from more narrow benchmarks like KernelBench that only let agents optimize kernels (which is a very valuable task, too!). The benchmark is intentionally open-ended, so the poor performance of the agents is not an underelicitation issue. The agents have everything needed to succeed, but they still fail because they are not yet reliable enough for this task.
Our results suggest an inverse scaling phenomenon: Claude Sonnet 4.6 and GLM-5 rank highly because they more often preserve simple, valid, high-performing final servers, while several larger models show stronger peak runs but lose utility through brittle final-state choices. This contrasts with benchmarks where rankings track raw capability (e.g., SWE-Bench, Terminal-Bench, PostTrainBench, FrontierSWE).
One of the primary bottlenecks we have clearly observed is the lack of diversity of strategies: nearly all agents just use vLLM, without exploring alternatives. Overall, proper exploration is lacking: the current agents are not ready to tackle broad enough goals and get stuck after the first found solution (such as vLLM). I’m sure future agents will do much better, but here is where we are now.
This benchmark is our 2nd one in a suite of benchmarks that will track the progress on AI R&D automation. We will develop many more benchmarks that will cover different aspects of AI R&D automation, culminating in recursive self-improvement. Stay tuned!
