Klaviyo MCP Server

Implementation Reference

• src/tools/events.js:43-68 (handler)

  Executes the tool logic: formats event data into Klaviyo API payload and sends POST request via klaviyoClient.post.

  async (params) => {
    try {
      // Format payload according to the latest API structure
      const payload = {
        data: {
          type: "event",
          attributes: {
            metric: params.metric,
            profile: params.profile,
            properties: params.properties || {},
            time: params.time || new Date().toISOString(),
            value: params.value !== undefined ? params.value : 0
          }
        }
      };
      
      const result = await klaviyoClient.post('/events/', payload);
      return {
        content: [{ type: "text", text: JSON.stringify(result, null, 2) }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `Error creating event: ${error.message}` }],
        isError: true
      };
    }

• src/tools/events.js:32-42 (schema)

  Zod schema validating input parameters for metric, profile, properties, time, and value.

  {
    metric: z.object({
      name: z.string().describe("Name of the metric")
    }).describe("Metric information for the event"),
    profile: z.object({
      email: z.string().email().describe("Email of the customer")
    }).describe("Profile information for the event"),
    properties: z.record(z.any()).optional().describe("Additional properties for the event"),
    time: z.string().optional().describe("ISO timestamp for the event"),
    value: z.number().optional().describe("Numeric value for the event")
  },

• src/tools/events.js:30-70 (registration)

  Registers the create_event tool on the MCP server with name, schema, handler function, and description.

  server.tool(
    "create_event",
    {
      metric: z.object({
        name: z.string().describe("Name of the metric")
      }).describe("Metric information for the event"),
      profile: z.object({
        email: z.string().email().describe("Email of the customer")
      }).describe("Profile information for the event"),
      properties: z.record(z.any()).optional().describe("Additional properties for the event"),
      time: z.string().optional().describe("ISO timestamp for the event"),
      value: z.number().optional().describe("Numeric value for the event")
    },
    async (params) => {
      try {
        // Format payload according to the latest API structure
        const payload = {
          data: {
            type: "event",
            attributes: {
              metric: params.metric,
              profile: params.profile,
              properties: params.properties || {},
              time: params.time || new Date().toISOString(),
              value: params.value !== undefined ? params.value : 0
            }
          }
        };
        
        const result = await klaviyoClient.post('/events/', payload);
        return {
          content: [{ type: "text", text: JSON.stringify(result, null, 2) }]
        };
      } catch (error) {
        return {
          content: [{ type: "text", text: `Error creating event: ${error.message}` }],
          isError: true
        };
      }
    },
    { description: "Create a new event in Klaviyo" }

• src/server.js:35-35 (registration)

  Invokes registerEventTools to register the create_event tool (among others) on the main MCP server.

  registerEventTools(server);

• src/klaviyo-client.js:182-189 (helper)

  Helper function post() used by the handler to make the API POST request with retry logic.

  export async function post(endpoint, data, fallbackFn) {
    return executeWithRetry(
      () => client.post(endpoint, data),
      'POST',
      endpoint,
      data,
      fallbackFn
    );