SendGrid MCP Server

Instructions

Implementation Reference

• src/tools/templates.ts:124-179 (handler)

  The handler function that executes the tool: checks read-only mode, constructs version data, handles optional fields, parses test_data if provided, and makes POST request to SendGrid API to create template version.

  handler: async ({ 
    template_id, 
    name, 
    subject, 
    html_content, 
    plain_content, 
    active, 
    generate_plain_content, 
    test_data 
  }: { 
    template_id: string; 
    name: string; 
    subject: string; 
    html_content: string; 
    plain_content?: string; 
    active?: number; 
    generate_plain_content?: boolean; 
    test_data?: string; 
  }): Promise<ToolResult> => {
    const readOnlyCheck = checkReadOnlyMode();
    if (readOnlyCheck.blocked) {
      return { content: [{ type: "text", text: readOnlyCheck.message! }] };
    }
    
    const versionData: any = {
      name,
      subject,
      html_content,
      active: active ?? 1,
      generate_plain_content: generate_plain_content ?? true,
    };
    
    if (plain_content) {
      versionData.plain_content = plain_content;
    }
    
    if (test_data) {
      try {
        versionData.test_data = JSON.parse(test_data);
      } catch (error) {
        return { content: [{ type: "text", text: "Error: test_data must be valid JSON" }] };
      }
    }
    
    const result = await makeRequest(`https://api.sendgrid.com/v3/templates/${template_id}/versions`, {
      method: "POST",
      body: JSON.stringify(versionData),
    });
    
    return { 
      content: [{ 
        type: "text", 
        text: `Template version created successfully!\n\n${JSON.stringify(result, null, 2)}\n\nYou can now use this template with the Mail API using template_id: ${template_id}` 
      }] 
    };
  },

• src/tools/templates.ts:110-123 (schema)

  Tool configuration including title, description, and Zod-based input schema defining parameters for creating a template version.

  config: {
    title: "Create Template Version",
    description: "Create a new version of a template with HTML content and settings",
    inputSchema: {
      template_id: z.string().describe("ID of the template to add version to"),
      name: z.string().describe("Name for this version"),
      subject: z.string().describe("Email subject line (supports Handlebars)"),
      html_content: z.string().describe("HTML content of the email template (supports Handlebars)"),
      plain_content: z.string().optional().describe("Plain text version (optional)"),
      active: z.number().optional().default(1).describe("Set as active version (1 = active, 0 = inactive)"),
      generate_plain_content: z.boolean().optional().default(true).describe("Auto-generate plain text from HTML"),
      test_data: z.string().optional().describe("JSON string of test data for Handlebars variables"),
    },
  },

• src/tools/index.ts:9-17 (registration)

  Aggregates all individual tool modules (including templateTools containing create_template_version) into allTools export.

  export const allTools = {
    ...automationTools,
    ...campaignTools,
    ...contactTools,
    ...mailTools,
    ...miscTools,
    ...statsTools,
    ...templateTools,
  };

• src/index.ts:21-23 (registration)

  Registers all tools from allTools to the MCP server using server.registerTool, including create_template_version.

  for (const [name, tool] of Object.entries(allTools)) {
    server.registerTool(name, tool.config as any, tool.handler as any);
  }