MCP Todo

Instructions

Implementation Reference

• src/server.ts:53-70 (registration)

  Registration of the 'list_todos' tool using server.registerTool, including schema and handler.

  server.registerTool(
    "list_todos",
    {
      title: "List Todos",
      description: "Return all todos in a structured format.",
      inputSchema: {},
      outputSchema: {
        todos: z.array(TodoSchema),
      },
    },
    async () => {
      const todos = await readTodos();
      return {
        structuredContent: { todos },
        content: [{ type: "text", text: JSON.stringify({ todos }, null, 2) }],
      };
    }
  );

• src/server.ts:63-69 (handler)

  The handler function for 'list_todos' that reads todos from storage and returns structured content.

  async () => {
    const todos = await readTodos();
    return {
      structuredContent: { todos },
      content: [{ type: "text", text: JSON.stringify({ todos }, null, 2) }],
    };
  }

• src/server.ts:11-15 (schema)

  Zod schema for Todo type, used in the outputSchema of list_todos.

  export const TodoSchema = z.object({
    id: z.number().int().positive(),
    title: z.string().min(1),
    done: z.boolean(),
  });

• src/server.ts:20-27 (helper)

  Helper function to read todos from the JSON file database.

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

• src/server.ts:55-62 (schema)

  Tool metadata including title, description, inputSchema (empty), and outputSchema referencing TodoSchema.

  {
    title: "List Todos",
    description: "Return all todos in a structured format.",
    inputSchema: {},
    outputSchema: {
      todos: z.array(TodoSchema),
    },
  },