How Memory Fails

Memory makes agents more capable, but it also introduces a whole new class of bugs that do not exist in stateless systems. This chapter catalogs them, drawing on the failure modes in the "Practical Guide" and the more formal taxonomy in the SSGM paper. Almost all of these are failures of the manage phase from Chapter 1: things go wrong not when memory is written or read, but in how it is maintained over time.

A theme to hold onto: in a stateless system, a mistake affects one response and then disappears. In a system with evolving memory, a mistake can be stored, reinforced, and acted on for a long time. The SSGM paper puts it crisply: unlike static RAG, where an error is isolated to a single retrieval, errors in evolving memory are cumulative and persistent.