Klaviyo MCP Server

Implementation Reference

• src/tools/templates.js:35-47 (handler)

  The main execution logic for the get_template tool: fetches template by ID via klaviyoClient.get and returns JSON or error response.

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

• src/tools/templates.js:32-34 (schema)

  Zod input schema defining the required 'id' parameter as a string.

  {
    id: z.string().describe("ID of the template to retrieve")
  },

• src/tools/templates.js:31-49 (registration)

  Direct registration of the 'get_template' tool using server.tool, including name, schema, handler, and description.

    "get_template",
    {
      id: z.string().describe("ID of the template to retrieve")
    },
    async (params) => {
      try {
        const template = await klaviyoClient.get(`/templates/${params.id}/`);
        return {
          content: [{ type: "text", text: JSON.stringify(template, null, 2) }]
        };
      } catch (error) {
        return {
          content: [{ type: "text", text: `Error retrieving template: ${error.message}` }],
          isError: true
        };
      }
    },
    { description: "Get a specific template from Klaviyo" }
  );

• src/server.js:40-40 (registration)

  High-level registration call to registerTemplateTools which includes the get_template tool registration.

  registerTemplateTools(server);

• src/klaviyo-client.js:135-180 (helper)

  The klaviyoClient.get() helper function called by the handler, handling URL building, caching, rate limiting retries, and error handling for Klaviyo API GET requests.

  export async function get(endpoint, params = {}, fallbackFn) {
    // Build the URL with query parameters according to Klaviyo API specs
    let url = endpoint;
    const queryParams = [];
    
    // Special handling for campaign endpoint - add required filter if missing
    if (endpoint === '/campaigns/' && !params.filter) {
      logger.debug('Adding default email filter for campaigns endpoint');
      params.filter = "equals(messages.channel,'email')";
    }
    
    // Handle filter parameter if provided
    if (params.filter) {
      queryParams.push(`filter=${encodeURIComponent(params.filter)}`);
    }
    
    // Handle include parameter if provided
    if (params.include) {
      queryParams.push(`include=${encodeURIComponent(params.include)}`);
    }
    
    // Handle page_size parameter if provided
    if (params.page_size) {
      queryParams.push(`page[size]=${params.page_size}`);
    }
    
    // Handle pagination cursor if provided
    if (params.page_cursor) {
      queryParams.push(`page[cursor]=${params.page_cursor}`);
    }
    
    // Add query parameters to URL
    if (queryParams.length > 0) {
      url = `${endpoint}?${queryParams.join('&')}`;
    }
    
    logger.debug(`Prepared GET request to: ${url}`);
    
    return executeWithRetry(
      () => client.get(url),
      'GET',
      endpoint,
      params,
      fallbackFn
    );
  }