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Phase 5

Memory Ranking

~2 min read

Concept & How It Works

    Why Does It Exist?

    Top-k vector search returns plausible but not always best results. Ranking ensures the most useful memories win the limited token budget.

    Real-World Analogy

    Memory ranking is a search engine's second page — vector search is the crawl; ranking is the algorithm that puts the best answer first.
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    Visual Workflows

    What is Memory Ranking?

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    Example

    Scenario

    Five memories match 'deployment.' Ranking boosts the one from yesterday about the staging deploy over a six-month-old note about deployment theory.

    Solution

    In Agent Memory, apply Memory Ranking to this scenario: Five memories match 'deployment. 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 Ranking (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 Ranking happens in the code.

    Memory Ranking
    1# Memory Ranking — 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 Ranking8    model="gpt-4o-mini",9    messages=[10        {"role": "system", "content": "You explain memory ranking clearly."},11        {"role": "user", "content": f"What is memory ranking?"},12    ],13    temperature=0,14)15print(response.choices[0].message.content)  # show output for debugging

    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 Memory Ranking as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for memory ranking

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Memory Ranking
    • Cross-Encoder
    • MMR
    • Recency Decay