Coding agents pass most checks, and still rarely finish the job
AspireAI community · arXiv (Co-Design Bench)
*Coding agents pass most checks, and still rarely finish the job.*
Co-Design Bench took 273 tasks from 26,314 real user coding sessions, so the requests are the messy ones people actually type rather than ones a benchmark author designed. Each task pairs a request with a runnable app and 2,331 hidden acceptance criteria, graded by a judge a second model then tries to refute.
Under one shared harness, the best of ten endpoints passed an average of 69.9 percent of the criteria per task but fully satisfied only 26.4 percent of tasks. Every endpoint did worse on repository edits spanning three or four kinds of change.
The honest limit: this measures ten endpoints under one harness, so it describes the shape of the gap rather than any single model.
https://arxiv.org/abs/2610.35138
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.