Prefix Executability: Evaluating Tool-Using Agents Beyond Final Success
Read the original on arXiv AI →The paper introduces prefix executability, a trajectory-level evaluation protocol for tool-using agents that checks whether every prefix of a predicted tool-call sequence remains executable under tool schemas, state preconditions, and data dependencies. It defines metrics such as Prefix Executability Curves, First-Error Depth, Trajectory Executability Rate, horizon-normalized AUC-PEC, and Recovery Rate to quantify reliability. Experiments on BFCL-v3, ToolSandbox, and $ au^3$-bench show that agents can achieve high final success while having low trajectory executability, revealing failure modes that final success metrics miss, and demonstrate that explicit pre-execution plan checking can improve prefix-level reliability without sacrificing terminal success.
Machine-generated by The Flow from the publisher's headline and feed description — not written or checked by a human. The full article lives at arXiv AI.