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Phase 5

Semantic Memory

~3 min read

Concept & How It Works

    Why Does It Exist?

    Agents need a fact layer separate from conversation logs. Semantic memory answers 'what do I know about X?' without replaying entire chat histories.

    Real-World Analogy

    Semantic memory is an encyclopedia entry about you — facts without the story of when you mentioned them.
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    Visual Workflows

    What is Semantic Memory?

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    Example

    Scenario

    Semantic memory holds: {user: 'Alice', stack: 'TypeScript', team_size: 8, preferred_linter: 'eslint'} — retrieved when Alice asks about CI setup.

    Solution

    In Agent Memory, apply Semantic Memory to this scenario: Semantic memory holds: {user: 'Alice', stack: 'TypeScript', team_size: 8, preferred_linter: 'eslint'} — retrieved when Alice asks about CI setup. 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 Semantic 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 Semantic Memory happens in the code.

    Semantic Memory
    1# Semantic Memory — 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 Semantic Memory8    model="gpt-4o-mini",9    messages=[10        {"role": "system", "content": "You explain semantic memory clearly."},11        {"role": "user", "content": f"What is semantic memory?"},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 Semantic Memory as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for semantic memory

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Semantic Memory
    • Fact Extraction
    • Knowledge Base
    • Entity Memory