Memory isn’t magic: 3 types of AI 'memory' (and when to use each)

If you’ve ever said “we should add memory to the app,” you’re not alone. It’s also the fastest way to start a week-long argument, because people use the word memory to mean totally different things . In practice, “memory” in AI products usually breaks down into three distinct systems : 1) Context (short-term memory) — what’s in the current prompt/window 2) Long‑term memory (facts) — durable information you can look up later 3) Procedural memory (rules + habits) — the system that prevents repeating mistakes This post is a beginner-friendly map of those three types, with small code snippets and a visual you can copy. If you like this kind of build log / agent engineering, I post updates here: https://t.me/the_prompt_and_the_code 1) Context: short-term “memory” inside the prompt What it is: The text (and other inputs) you send to the model right now . What it’s good for: continuing a conversation keeping a consistent writing style doing multi-step tasks (“first do X, then Y”) What it’s no