Fake Store API MCP Server

Instructions

Implementation Reference

• src/tools/carts.ts:41-45 (handler)

  Core handler function that validates the userId and fetches the user's carts from the FakeStore API endpoint `/carts/user/${userId}`.

  export async function getUserCarts(args: { userId: number }): Promise<Cart[]> {
    const { userId } = args;
    validatePositiveInteger(userId, 'User ID');
    return get<Cart[]>(`/carts/user/${userId}`);
  }

• src/index.ts:131-136 (handler)

  MCP server dispatch handler that calls the getUserCarts function and formats the response as MCP content.

  if (name === 'fakestore_get_user_carts') {
    const result = await getUserCarts(args as { userId: number });
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
    };
  }

• src/tools/carts.ts:152-164 (schema)

  Tool schema definition including name, description, and inputSchema for validation.

  {
    name: 'fakestore_get_user_carts',
    description: 'Get all carts belonging to a specific user',
    inputSchema: {
      type: 'object',
      properties: {
        userId: {
          type: 'number',
          description: 'User ID',
        },
      },
      required: ['userId'],
    },

• src/index.ts:40-44 (registration)

  Registration of all tools including cartTools (which contains fakestore_get_user_carts) in the MCP server's listTools handler.

  server.setRequestHandler(ListToolsRequestSchema, async () => {
    return {
      tools: [...productTools, ...cartTools, ...userTools],
    };
  });