Klaviyo MCP Server

Implementation Reference

• src/tools/campaigns.js:79-98 (registration)

  Registration of the 'get_campaign_messages' MCP tool, including inline Zod input schema, async handler function that fetches campaign messages from Klaviyo API using klaviyoClient, error handling, and tool description.

  server.tool(
    "get_campaign_messages",
    {
      campaign_id: z.string().describe("ID of the campaign to retrieve messages for")
    },
    async (params) => {
      try {
        const messages = await klaviyoClient.get(`/campaigns/${params.campaign_id}/campaign-messages/`);
        return {
          content: [{ type: "text", text: JSON.stringify(messages, null, 2) }]
        };
      } catch (error) {
        return {
          content: [{ type: "text", text: `Error retrieving campaign messages: ${error.message}` }],
          isError: true
        };
      }
    },
    { description: "Get all messages for a specific campaign" }
  );

• src/server.js:37-37 (registration)

  Invocation of registerCampaignTools to register all campaign-related tools on the MCP server, including 'get_campaign_messages'.

  registerCampaignTools(server);

• src/tools/campaigns.js:84-96 (handler)

  The core handler function for executing the 'get_campaign_messages' tool logic: calls Klaviyo API endpoint for campaign messages and returns JSON response or error.

  async (params) => {
    try {
      const messages = await klaviyoClient.get(`/campaigns/${params.campaign_id}/campaign-messages/`);
      return {
        content: [{ type: "text", text: JSON.stringify(messages, null, 2) }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `Error retrieving campaign messages: ${error.message}` }],
        isError: true
      };
    }
  },

• src/tools/campaigns.js:81-83 (schema)

  Zod schema defining the input parameter 'campaign_id' for the tool.

  {
    campaign_id: z.string().describe("ID of the campaign to retrieve messages for")
  },