UserLM-2.0 produced valid simulated conversations 46.2% of the time, more than three times the previous best user simulator
AspireAI community · arXiv (cs.CL)
Testing an AI assistant across a long multi-turn conversation needs a user simulator, and existing ones force a trade-off: prompted assistants can follow a complex intent but behave unnaturally, while purpose-built simulators sound realistic but drift off the user's actual goal. This work trains a simulator with reinforcement learning that rewards task-intent adherence and conversational naturalness together, and operationalizes naturalness using a lightweight discriminator trained against the simulator in an alternating adversarial loop. The resulting UserLM-2.0 met both criteria on 46.2% of conversations, against 14.1% for the strongest prior user simulator. The honest limitation is that the metric is the paper's own validity criterion, and the paper is a preprint in submission rather than a peer-reviewed result.
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