Klaviyo MCP Server

Implementation Reference

• src/tools/tags.js:36-58 (handler)

  The handler function for 'create_tag' tool. Constructs the tag payload and sends a POST request to Klaviyo's /tags/ endpoint using klaviyoClient, returns the result or error.

  async (params) => {
    try {
      const payload = {
        data: {
          type: "tag",
          attributes: {
            name: params.name,
            tag_type: params.tag_type
          }
        }
      };
      
      const result = await klaviyoClient.post('/tags/', payload);
      return {
        content: [{ type: "text", text: JSON.stringify(result, null, 2) }]
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: `Error creating tag: ${error.message}` }],
        isError: true
      };
    }
  },

• src/tools/tags.js:32-35 (schema)

  Zod input schema for 'create_tag' tool: requires 'name' (string) and 'tag_type' (enum: 'system' or 'custom').

  {
    name: z.string().describe("Name of the tag"),
    tag_type: z.enum(["system", "custom"]).describe("Type of tag")
  },

• src/tools/tags.js:30-60 (registration)

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

  server.tool(
    "create_tag",
    {
      name: z.string().describe("Name of the tag"),
      tag_type: z.enum(["system", "custom"]).describe("Type of tag")
    },
    async (params) => {
      try {
        const payload = {
          data: {
            type: "tag",
            attributes: {
              name: params.name,
              tag_type: params.tag_type
            }
          }
        };
        
        const result = await klaviyoClient.post('/tags/', payload);
        return {
          content: [{ type: "text", text: JSON.stringify(result, null, 2) }]
        };
      } catch (error) {
        return {
          content: [{ type: "text", text: `Error creating tag: ${error.message}` }],
          isError: true
        };
      }
    },
    { description: "Create a new tag in Klaviyo" }
  );

• src/server.js:42-42 (registration)

  Invocation of registerTagTools(server) which registers the 'create_tag' tool (and other tag tools) on the MCP server.

  registerTagTools(server);