MCP Todo

Instructions

Implementation Reference

• src/server.ts:79-85 (handler)

  The handler function that implements the add_todo tool logic: loads todos, generates next ID, appends new todo with given title (done=false), saves to file, returns success message.

  async ({ title }) => {
    const todos = await readTodos();
    const id = (todos.at(-1)?.id ?? 0) + 1;
    todos.push({ id, title, done: false });
    await writeTodos(todos);
    return { content: [{ type: "text", text: `Added #${id}: ${title}` }] };
  }

• src/server.ts:77-77 (schema)

  Input schema definition for the add_todo tool, validating the 'title' parameter as a non-empty string.

  inputSchema: { title: z.string().min(1) },

• src/server.ts:72-86 (registration)

  The server.registerTool call that registers the 'add_todo' tool with its schema and handler.

  server.registerTool(
    "add_todo",
    {
      title: "Add Todo",
      description: "Add a todo item",
      inputSchema: { title: z.string().min(1) },
    },
    async ({ title }) => {
      const todos = await readTodos();
      const id = (todos.at(-1)?.id ?? 0) + 1;
      todos.push({ id, title, done: false });
      await writeTodos(todos);
      return { content: [{ type: "text", text: `Added #${id}: ${title}` }] };
    }
  );

• src/server.ts:20-27 (helper)

  Helper function to read the list of todos from the persistent JSON file, returning empty array if not found.

  async function readTodos(): Promise<Todo[]> {
    try {
      const s = await fs.readFile(DB_PATH, "utf-8");
      return JSON.parse(s);
    } catch {
      return [];
    }
  }

• src/server.ts:28-30 (helper)

  Helper function to persist the list of todos to the JSON file.

  async function writeTodos(todos: Todo[]) {
    await fs.writeFile(DB_PATH, JSON.stringify(todos, null, 2), "utf-8");
  }