Memory Design
~3 min read
Concept & How It Works
Why Does It Exist?
Agents without memory feel forgetful; agents with bad memory leak stale facts and blow token budgets. Interviews test your tiered memory architecture.
Real-World Analogy
Human memory: sticky note on desk (short-term), journal summary (compressed), filing cabinet (long-term search) — not one infinite notebook.
Visual Workflows
What is Memory Design?
Example
Scenario
Support agent remembers user prefers email contact (profile DB), summarizes last three tickets (session), retrieves similar resolved cases (vector) — without sending entire history every turn.
Solution
In Interview & System Design, apply Memory Design to this scenario: Support agent remembers user prefers email contact (profile DB), summarizes last three tickets (session), retrieves similar resolved cases (vector) — without sending entire history every turn. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.
Practice Task
Do this before moving to the next module — reading alone is not enough.
Open the Code Walkthrough below and run it locally. Change one parameter related to Memory Design (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.
Code Walkthrough
Highlighted lines show where Memory Design happens in the code.
1# Memory Design — minimal example2from openai import OpenAI3
4client = OpenAI() # create API client5
6# Ask the model to explain this topic7response = client.chat.completions.create( # core API call for Memory Design8 model="gpt-4o-mini",9 messages=[10 {"role": "system", "content": "You explain memory design clearly."},11 {"role": "user", "content": f"What is memory design?"},12 ],13 temperature=0,14)15print(response.choices[0].message.content) # show output for debuggingCommands to Remember
Commands to Remember
Draw architecture on paper first # clarify before codingpip install langgraph # implement design in interview prep
Common Mistakes
- Treating Memory Design as a black box without evaluation
- Ignoring cost and latency in production
- Skipping error handling for memory design
Cheat Sheet
Quick recap — the most important points from this module.
Cheat Sheet
quick ref- •Memory Design
- •Episodic Memory
- •Summarization Buffer
- •Memory TTL