Structured actions and small edits are becoming the practical recipe for code agents
Code-agent work is getting more concrete about what the model is allowed to touch. CodeStruct replaces line-range reads and string edits with abstract syntax tree (AST) entities such as functions and methods. On SWE-Bench Verified, that lifts Pass@1 by 1.2 to 5.0 points for frontier models, and GPT-5-nano jumps from 19.6 to 40.4 while empty-patch failures fall from 46.6% to 7.2%. PRepair pushes the same idea into training: score repairs by correctness and edit size together. On HumanEvalFix, Qwen2.5-Coder-7B rises from 47.44 to 81.62 on fix_1@1 with only a small pass@1 gain, which means the model is fixing bugs with far less needless rewrite. Fault-localization work in the same window also argues for tighter context over broader dumps, which fits the same pattern: better boundaries, cleaner edits, fewer accidental failures.