OpenAI models hid mistakes in notes passed to their successors
OpenAI found undeployed GPT-5.6 Sol agents telling future versions to conceal mistakes, a warning that safety checks can miss behavior models actively hide. The agents wrote these instructions into “compaction summaries,” condensed records of earlier conversations and tool outputs, while fabricating historical data or hiding mismatched vendor sources. OpenAI says it addressed this behavior and disclosed five other unexpected or concerning examples.