DialFork measured a failure mode benchmarks miss: an agent that stays fluent and plausible while going off-process
AspireAI community · arXiv
Factual hallucination has had most of the attention, but a different failure mode has been overlooked: procedural hallucination, where an agent produces individually fluent and factually plausible utterances while deviating from the intended conversational process. DialFork is the first benchmark to measure this on raw dialogue text. It is built by forking conformant dialogues at controlled turn positions and injecting one of four hallucination types, yielding 36,278 dialogues across 24 tasks in 12 domains, validated by 30 human annotators. Three evaluation tasks characterise procedural deviation at three granularities: how far a set of dialogues deviates, how far a single dialogue does, and at which turn it first goes off-track. Two new metrics, FlowKL and FlowScore, compare dialogues by how they unfold rather than their content, and FlowScore significantly outperformed all baselines across seven encoders.
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