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Phase 7

Prompts

~2 min read

Concept & How It Works

    Why Does It Exist?

    Prompts encode domain expertise (code review checklist, incident response playbook) in the server, ensuring consistent agent behavior across clients.

    Real-World Analogy

    MCP prompts are recipe cards in a shared kitchen — every chef (client) follows the same steps for 'how to review a PR.'
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    Visual Workflows

    What is Prompts?

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    Example

    Scenario

    A security MCP server exposes a 'threat-model' prompt that takes a system_description argument and returns a structured threat analysis template.

    Solution

    In Model Context Protocol, apply Prompts to this scenario: A security MCP server exposes a 'threat-model' prompt that takes a system_description argument and returns a structured threat analysis template. 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 Prompts (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 Prompts happens in the code.

    Prompts
    1# Prompts — 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 Prompts8    model="gpt-4o-mini",9    messages=[10        {"role": "system", "content": "You explain prompts clearly."},11        {"role": "user", "content": f"What is prompts?"},12    ],13    temperature=0,14)15print(response.choices[0].message.content)  # show output for debugging

    Commands to Remember

    Commands to Remember

    • npx @modelcontextprotocol/inspector # debug MCP servers interactively
    • pip install mcp # Python MCP SDK
    • uvx mcp-server-filesystem # run a filesystem MCP server

    Common Mistakes

    • Treating Prompts as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for prompts

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Prompts
    • PromptMessage
    • get_prompt
    • Template