The First Token Knows: Single-Decode Confidence for Hallucination Detection

ArXi:2605.05166v1 Announce Type: cross Self-consistency detects hallucinations by generating multiple sampled answers to a question and measuring agreement, but this requires repeated decoding and can be sensitive to lexical variation. Semantic self-consistency improves this by clustering sampled answers by meaning using natural language inference, but it adds both sampling cost and external inference overhead.