How to Answer
“They’re three different things, and people use the words interchangeably, which is exactly why memory bugs are so hard to talk about.
The context window is a hard limit on the model — how many tokens it can attend to in one call. It belongs to the model, it costs money every call, and it is gone the moment the call returns. The model is stateless; nothing persists inside it.
Conversation history is what you choose to resend. It’s your buffer of prior turns, and it’s the thing that grows until it no longer fits. Windowing, summarising and eviction all live here.
Memory is what survives the conversation — preferences, facts, past decisions — stored outside the model and retrieved back into the window when it’s relevant. It is a database you own, with all the ordinary database problems.
The practical consequence is that ‘the agent forgot’ is three different bugs: it never wrote the fact, it wrote it but didn’t retrieve it, or it retrieved it and your history policy then trimmed it back out.”