ResearchResearch paperReinforcement Learning1 source · Oct 18, 2026

Over-Defense in Coding Agents Begins at Silent Forks

Language models behind coding agents are post-trained with outcome rewards, and recent methods concentrate credit on the turns that decide the outcome.

Key points

  • We find that defensive actions beyond what a task requires escape both.
  • They begin at silent forks, the turns where every next action leads to the same outcome.
  • This motivates a rethink of where learning signals belong, namely where behavior diverges, which a behavioral checker can locate and the outcome cannot.
  • Our method, ForkDPO, contrasts a proportionate and a disproportionate action at the same prefix, at silent forks on both sides of the required behavior.

Sources (1)

  • [1]Over-Defense in Coding Agents Begins at Silent Forks
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 18, 01:56 AM
    Language models behind coding agents are post-trained with outcome rewards, and recent methods concentrate credit on the turns that decide the outcome.
    We find that defensive actions beyond what a task requires escape both.

Extractive summary: sentences quoted from the sources.

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