Confidence Comes from Experience: Experiential Confidence Estimation from Reasoning to Agents

XConf estimates LLM confidence from accumulated past episodes, improving calibration and discrimination across nine benchmarks at one-tenth self-consistency cost.

Researchers propose XConf, an experiential confidence estimator that augments current inference with a stored record of the model's graded past episodes, including reflections, stated confidence, outcomes, and lessons. A Recall stage retrieves episodes from similar tasks with similar stated confidence and reads off historical success rates, while a Reflect stage prompts the model to name recurring failure modes and restate confidence. Across nine benchmarks in reasoning, coding, multimodal QA, and interactive agents, and four models from three families, XConf beats or matches ten-sample self-consistency in AUROC on 23 of 24 comparisons with much lower ECE, at a tenth of the generation cost. For selective prediction, abstaining on the 10% least-confident episodes raises delivered success rate by up to 8.7 points on agent tasks.