Confirm It Loads & Lists Tools
Check that your tool shows up and is callable.
Confirm It Loads & Lists Tools is a free MCP Academy lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the MCP Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Does It Actually Work?
Your server runs, but how do you know it's healthy? Let's verify that it loads and that your tool shows up where clients can see it. 🔍
The Dev Command
The SDK ships a helper for this. Running mcp dev on your file launches the server with a visual inspector attached.
uv run mcp dev server.pyMeet the Inspector
That opens the MCP Inspector in your browser: a friendly panel for poking at your server without writing any client code.
Connect First
In the Inspector you click Connect. That runs the handshake; if it succeeds, your server loaded and is speaking MCP correctly.
Open the Tools Tab
Now switch to the Tools tab. This calls the protocol's list operation and shows every tool your server advertises.
See Your Tool Listed
You should spot your function there by name, like "hello" or "greet", alongside the description that came from its docstring.
Check the Input Schema
Click the tool and the Inspector shows its schema, the typed parameters FastMCP built from your hints. This is what the model reads.
Call It Live
Fill in any arguments and hit run. The Inspector invokes your tool and shows the exact result the model would receive back.
Empty List Is a Clue
If the Tools list is empty, your decorator probably didn't run. Make sure @mcp.tool() sits directly above the function.
Listing Under the Hood
That tab is just a UI over a real message: the client sends a tools/list request and your server replies with the catalog.
Inspect Resources Too
The Inspector isn't only for tools. It has tabs for resources and prompts too, so you can verify every capability your server exposes.
Quick Check
What does the Inspector's Tools tab actually do under the hood?
Recap
You launched mcp dev, connected in the Inspector, saw your tool listed, and even called it live. Your first server is real and verified. Congrats! 🎉
Frequently asked questions
Is the “Confirm It Loads & Lists Tools” lesson free?
Yes — the full text of “Confirm It Loads & Lists Tools” is free to read here on the web, and the MCP Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the MCP Academy course, upgrade to CoddyKit PRO.
What will I learn in “Confirm It Loads & Lists Tools”?
Check that your tool shows up and is callable. You practise MCP Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start MCP Academy?
No prior experience is required. MCP Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Confirm It Loads & Lists Tools” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this MCP Academy lesson?
Yes. Every MCP Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Create a FastMCP Instance
- Add a Hello Tool
- Run the Server with stdio
- Confirm It Loads & Lists Tools