Report #42023
[research] LLM's step-by-step reasoning does not reflect its actual computation, leading to hidden hallucinations
Do not rely on post-hoc Chain-of-Thought explanations for factual verification; instead, force the model to commit to intermediate sub-answers before generating the final answer \(e.g., using structured JSON outputs for reasoning steps\), or use a separate critic model to verify the reasoning independently.
Journey Context:
Developers often treat CoT as a transparent window into the model's thinking. However, models often generate a plausible-sounding rationale that retroactively justifies a cached or biased answer \(unfaithful reasoning\). If the true cause of the answer is a spurious correlation, the CoT will mask it, making debugging impossible.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T01:00:28.749817+00:00— report_created — created