ShipStation API MCP Server

Implementation Reference

• src/tools/carrier-tools.js:49-61 (handler)

  The main handler function for the 'list_carrier_services' tool. It takes carrierCode as input, calls shipStationClient.getCarrierServices, and returns the services as formatted JSON or an error message.

  handler: async ({ carrierCode }) => {
    try {
      const services = await shipStationClient.getCarrierServices(carrierCode);
      return {
        content: [{ type: "text", text: JSON.stringify(services, null, 2) }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: error.message }],
        isError: true
      };
    }
  }

• src/tools/carrier-tools.js:46-48 (schema)

  Zod schema defining the input parameter 'carrierCode' as a required string with description.

  schema: {
    carrierCode: z.string().describe("Carrier code (e.g., 'ups', 'fedex', 'usps')")
  },

• src/server.js:173-191 (registration)

  Tool registration loop in the MCP server that spreads the carrierTools array (among others) and registers each tool by calling server.tool with its name, schema, handler, and description.

  // Register all tools
  [
    ...orderTools,
    ...shipmentTools,
    ...carrierTools,
    ...warehouseTools,
    ...productTools,
    ...customerTools,
    ...storeTools,
    ...webhookTools,
    ...fulfillmentTools
  ].forEach(tool => {
    server.tool(
      tool.name,
      tool.schema,
      tool.handler,
      { description: tool.description }
    );
  });

• src/api-client.js:110-112 (helper)

  Helper method in ShipStationClient that performs the actual API request to ShipStation's /carriers/listservices endpoint with the carrierCode parameter.

  async getCarrierServices(carrierCode) {
    return this.request('GET', '/carriers/listservices', null, { carrierCode });
  }