Revenue Engine MCP

Instructions

Implementation Reference

• index.js:678-680 (handler)

  Handler for the search_gmail tool. Dispatches tool execution to the callAPI helper function with action 'searchGmail' and tool arguments.

  case "search_gmail":
    result = await callAPI("searchGmail", args);
    break;

• index.js:337-349 (schema)

  Input schema for search_gmail tool defining parameters: query (string, Gmail search syntax) and maxResults (number).

  inputSchema: {
    type: "object",
    properties: {
      query: {
        type: "string",
        description: "Gmail search query (default: 'is:unread')"
      },
      maxResults: {
        type: "number",
        description: "Max results (default: 25, max: 100)"
      }
    }
  }

• index.js:334-350 (registration)

  Registration of the search_gmail tool in the MCP server's tool list, including name, description, and input schema.

  {
    name: "search_gmail",
    description: "Search Gmail inbox. Use Gmail search syntax like 'from:email@example.com' or 'is:unread' or 'subject:proposal'",
    inputSchema: {
      type: "object",
      properties: {
        query: {
          type: "string",
          description: "Gmail search query (default: 'is:unread')"
        },
        maxResults: {
          type: "number",
          description: "Max results (default: 25, max: 100)"
        }
      }
    }
  },

• index.js:74-131 (helper)

  Shared helper function callAPI used by search_gmail (and other tools) to proxy requests to the Google Apps Script backend at the configured API_URL with the specified action and parameters.

  async function callAPI(action, data = {}) {
    debugLog('=== API CALL START ===');
    debugLog(`Action: ${action}`);
    debugLog(`Data: ${JSON.stringify(data)}`);
  
    try {
      // Build form-encoded body for POST
      const formData = new URLSearchParams();
      formData.append('action', action);
  
      // Add all data fields to form
      for (const [key, value] of Object.entries(data)) {
        if (value !== undefined && value !== null) {
          formData.append(key, value.toString());
        }
      }
  
      const formString = formData.toString();
      debugLog(`FormData: ${formString}`);
      debugLog(`API_URL: ${API_URL}`);
  
      // Use POST with proper content type
      const response = await fetch(API_URL, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: formString
      });
  
      debugLog(`Response status: ${response.status}`);
      debugLog(`Response ok: ${response.ok}`);
  
      if (!response.ok) {
        debugLog(`Response not OK: ${response.status} ${response.statusText}`);
        throw new Error(`API request failed: ${response.status} ${response.statusText}`);
      }
  
      const text = await response.text();
      debugLog(`Response text length: ${text.length}`);
      debugLog(`Response text: ${text}`);
  
      if (!text) {
        debugLog('ERROR: Empty response from API');
        throw new Error('Empty response from API');
      }
  
      const parsed = JSON.parse(text);
      debugLog(`Parsed successfully: ${JSON.stringify(parsed)}`);
      debugLog('=== API CALL END ===');
      return parsed;
  
    } catch (error) {
      debugLog(`ERROR in callAPI: ${error.message}`);
      debugLog(`ERROR stack: ${error.stack}`);
      throw error;
    }
  }