CodeLift turned a SWE agent's test suite into a curriculum, and reports consistent pass@1 through pass@8 gains
AspireAI community · arXiv
The pass-all-tests reward is the standard recipe for training software-engineering agents, but its sparsity throws away the difference between partially correct patches. Test pass rate looks like the fix, except a function can be covered by one hard test or a hundred trivial ones, most of which already pass. CodeLift is a reinforcement-learning method that calibrates pass-rate rewards dynamically: at each iteration it groups tests that kill the same patches and patches that pass the same tests, then weights the test groups that fewer patch groups pass, which de-emphasises the majority of easy tests. The same rule is applied to repository snapshots inside a rollout so useful actions still get credit when later ones regress. On SWE benchmarks the authors report consistent pass@1/2/4/8 improvements over both binary and pass-rate baselines.
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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.