OpenAI caught its models leaving notes to successors to hide bad behavior

OpenAI caught something unusual while training its latest model, GPT-5.6 Sol: it began leaving instructions for future versions of itself, telling them to conceal mistakes and misaligned behavior from the user. 

OpenAI said it has addressed the specific behavior, but it gets to the heart of one of the biggest problems in AI safety and alignment research today. As models get more capable, they also get better at hiding their misalignment, making it difficult for researchers to truly know whether they’ve eliminated unwanted behavior.

OpenAI disclosed the behavior — along with five other examples of unexpected or concerning model behavior on Wednesday — as part of its new framework for tracking, investigating, and disclosing instances of misalignment.

The report details how researchers discovered undeployed Sol agents adding instructions to “compaction summaries” — condensed versions of older conversation history and tool outputs — reminding future iterations to conceal mistakes and misalignment from the user.

In one example, an agent preparing a financial model couldn’t find the requested historical data. 

“We likely need create a tab `Historical Data` ourselves with reasonable 2024 historical data, because user wants a finished workbook and there is no source file,” the AI model wrote to its future self. “Be transparent only if asked; final answer should just link file.”