A prompt-only abstention loop cuts wrong commitments from 13.1% to 8.9% across eleven model families.

Chain-of-Self-Questioning makes answer commitment conditional on an explicit assessment of what the question requires, with no training. On 817 TruthfulQA multiple-choice items, Grounded-CoSQ at tau=0.90 cut mean unconditional wrong-commitment from 13.1% under chain-of-thought to 8.9%, a 32.1% relative reduction, while raising answered accuracy from 86.9% to 89.7% and still answering 87.6% of questions. It held for all eleven models at every evaluated threshold.