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Phase 5

Long-Term Memory

~2 min read

Concept & How It Works

    Why Does It Exist?

    Short-term memory resets. Long-term memory makes agents feel personal and competent over weeks of interaction.

    Real-World Analogy

    Long-term memory is a CRM record on every customer — the agent 'knows' you even if the current chat just started.
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    Visual Workflows

    What is Long-Term Memory?

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    Example

    Scenario

    After three sessions, the agent recalls you use Python 3.12, deploy on AWS, and dislike verbose logging — injected into the system prompt automatically.

    Solution

    In Agent Memory, apply Long-Term Memory to this scenario: After three sessions, the agent recalls you use Python 3. 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 Long-Term Memory (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 Long-Term Memory happens in the code.

    Long-Term Memory
    1def recall_memories(user_id, query, vector_store, k=5):  # define a reusable function2    results = vector_store.similarity_search(  # key line for Long-Term Memory3        query,4        k=k,5        filter={"user_id": user_id},6    )7    return "\n".join(r.page_content for r in results)  # return the result

    Commands to Remember

    Commands to Remember

    • pip install chromadb # vector store for long-term memory
    • pip install redis # fast session / working memory
    • pip install tiktoken # count tokens before injecting memory

    Common Mistakes

    • Treating Long-Term Memory as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for long term memory

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Long-Term Memory
    • Persistent Store
    • Memory Extraction
    • User Profile