'Constraint Decay' Paper Reveals LLM Agents Fail at Production Backend Code — 280 Points, 190 Comments

arXiv / Hacker News·high signal

A new paper (arXiv:2605.06445) introduces 'constraint decay' — the phenomenon where LLM agent performance drops substantially as structural requirements accumulate in backend code generation. Tested across 80 greenfield and 20 feature tasks in eight web frameworks, agents excelled at unconstrained generation but failed to adhere to architectural patterns, ORMs, and database constraints. The authors open-sourced the full evaluation pipeline and agent trajectories.