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ai-workflow-course/modules/20-mcp-servers-giving-the-ai-hands/lab/tasks_mcp_server.py
T
claude fbec36cb67 feat(course): build out all 27 modules, capstone, scaffold, and conventions
Scaffold the course repo and author the full curriculum in dependency-chain
order, following the settled build decisions in handoff.md.

- Scaffold: course README, vendor-neutral AGENTS.md (dogfoods Module 5),
  _TEMPLATE.md (the fixed 9-section module shape), root .gitignore, ship config.
- Modules 1-2: reference exemplars (locked for tone/depth/lab style).
- Modules 3-27: full lessons + runnable labs, each following the template,
  respecting the chain, vendor/model-agnostic, with "feel the pain" labs.
- Module 8 hosting comparison web-researched and date-stamped (as of 2026-06-22),
  not written from memory; expansion-zone modules carry Verify-before-publish.
- Capstone: the full loop end to end on the running tasks-app example.

Lab code syntax-checked (Python/shell/YAML); every module has the 7 core
template sections.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TfzV5QvtPDz8LJS3Pu5VLT
2026-06-22 12:18:30 -04:00

66 lines
2.1 KiB
Python

"""A tiny MCP server that gives an AI client hands on the tasks-app.
It exposes the tasks-app over the Model Context Protocol (MCP) so an agentic tool can read and
change your real task list directly — no copy-paste, no pasting tasks.json into a chat window.
The whole server is the decorated functions below. FastMCP (from the official Python SDK) turns
each `@mcp.tool()` function into a tool the AI client can discover and call. That's it — a tool is
a normal Python function plus a docstring the client reads to know what it does.
Setup (once):
pip install "mcp[cli]"
Drop this file into your tasks-app folder, next to tasks.py and cli.py (it reuses them, and shares
the same tasks.json — so a task the AI adds through this server shows up in `python cli.py list`).
Sanity-check that it starts (it will sit waiting for a client to talk to it; Ctrl-C to stop):
python tasks_mcp_server.py
You don't normally run it by hand, though. Your agentic tool launches it for you — see the lab.
"""
import json
from pathlib import Path
from mcp.server.fastmcp import FastMCP
from tasks import Task, TaskList
STATE = Path(__file__).parent / "tasks.json"
# The name is how the server identifies itself to the client.
mcp = FastMCP("tasks")
def _load() -> TaskList:
if not STATE.exists():
return TaskList()
raw = json.loads(STATE.read_text())
return TaskList(tasks=[Task(**t) for t in raw])
def _save(tlist: TaskList) -> None:
STATE.write_text(json.dumps([t.__dict__ for t in tlist.tasks], indent=2))
@mcp.tool()
def list_tasks() -> str:
"""List every task in the tasks-app, with its index and whether it's done."""
return _load().render()
@mcp.tool()
def add_task(title: str) -> str:
"""Add a new task to the tasks-app. `title` is the text of the task to add."""
tlist = _load()
tlist.add(title)
_save(tlist)
return f"added: {title}"
if __name__ == "__main__":
# stdio transport by default: the client launches this process and talks to it over
# stdin/stdout. That's why the server "just sits there" when you run it by hand — it's
# waiting for a client on the other end of the pipe.
mcp.run()