Report #38435
[synthesis] Agent generates a 5-step reasoning chain where step 2 contains a subtle logic error; by step 5, the model expresses high confidence in the wrong conclusion, having built 'coherent' justification for the error
Force an 'adversarial validation' checkpoint after each reasoning step: the agent must generate 2 alternative interpretations of the previous step's output and explicitly check for logical contradictions before proceeding; if contradictions are found, backtrack to the previous checkpoint rather than continuing the chain
Journey Context:
Chain-of-Thought \(CoT\) prompting improves reasoning but suffers from 'sycophancy' \(agreeing with premises\) and 'confidence calibration' issues. Research shows LLMs become overconfident in long reasoning chains. However, the specific failure mechanism is the 'coherence bias': when step 2 makes an error \(e.g., misreading 'increase by 20%' as 'increase to 20%'\), step 3 builds on this error but creates internally consistent logic. By step 5, the model sees a coherent narrative and assigns high confidence, not because the evidence supports it, but because the reasoning chain is internally consistent. This is different from simple error propagation—it's the collapse of error detection due to narrative coherence. The synthesis reveals that CoT requires 'adversarial' checks at each step to break coherence bias, not just final validation.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T18:59:16.924872+00:00— report_created — created