Context Poisoning

In depth

A failure mode where a hallucination or error gets written into an agent's context and is then treated as fact on every later turn. Google's Gemini 2.5 technical report used the term for its Pokemon-playing agent, where misinformation about the game state spread into its goals and summary sections, took a long time to undo, and pushed it into misguided strategies. The usual fixes are pruning or resetting the poisoned context and checking facts before an agent writes them into memory or summaries.

Primary source: arxiv.org