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Phase 7

Tools

~2 min read

Concept & How It Works

    Why Does It Exist?

    MCP tools replace per-framework tool definitions. Write one tool schema on the server; every MCP client discovers and calls it identically.

    Real-World Analogy

    MCP tools are standardized power outlets — any MCP client can plug in, regardless of who manufactured the server.
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    Visual Workflows

    What is Tools?

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    Example

    Scenario

    A GitHub MCP server exposes tools: create_issue, search_code, get_pull_request. Cursor's agent calls search_code to find relevant files in a repo.

    Solution

    In Model Context Protocol, apply Tools to this scenario: A GitHub MCP server exposes tools: create_issue, search_code, get_pull_request. 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 Tools (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 Tools happens in the code.

    Tools
    1# Tools — 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 Tools8    model="gpt-4o-mini",9    messages=[10        {"role": "system", "content": "You explain tools clearly."},11        {"role": "user", "content": f"What is tools?"},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 Tools as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for tools

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Tools
    • inputSchema
    • CallToolResult
    • Tool Discovery