Tessie MCP Extension

Instructions

Implementation Reference

• src/index.ts:1168-1219 (handler)

  MCP tool registration and handler for 'get_vehicles'. Fetches vehicles using TessieClient and returns formatted list in MCP-compliant response format.

  server.tool(
    "get_vehicles",
    "List all vehicles in the Tessie account",
    {},
    async () => {
      try {
        const vehicles = await tessieClient.getVehicles();
        const result = {
          total_vehicles: vehicles.length,
          vehicles: vehicles.map(vehicle => ({
            vin: vehicle.vin,
            display_name: vehicle.display_name
          }))
        };
  
        // Wrap in MCP format
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(result, null, 2)
            }
          ]
        };
      } catch (error) {
        const enhancedError = ErrorHandler.classifyError(error);
  
        if (ErrorHandler.shouldDegrade(enhancedError)) {
          const fallbackData = {
            status: 'degraded',
            error_type: enhancedError.type,
            message: enhancedError.userFriendly,
            suggestion: enhancedError.suggestion,
            vehicles: [],
            fallback_note: 'Vehicle list temporarily unavailable. Try again in a few moments.'
          };
  
          // Wrap error fallback in MCP format
          return {
            content: [
              {
                type: "text",
                text: JSON.stringify(fallbackData, null, 2)
              }
            ]
          };
        }
  
        throw new Error(ErrorHandler.formatErrorForUser(enhancedError));
      }
    }
  );

• src/tessie-client.ts:221-243 (helper)

  TessieClient.getVehicles() method: Core implementation that queries the Tessie API /vehicles endpoint and extracts VIN/display_name.

  async getVehicles(): Promise<Array<{ vin: string; display_name: string }>> {
    return ErrorHandler.withRetry(async () => {
      const response: AxiosResponse<{ results: any[] } | any[]> =
        await this.client.get('/vehicles');
  
      // Handle both old and new API response formats
      let vehicles: any[];
      if (response.data && typeof response.data === 'object' && 'results' in response.data) {
        vehicles = response.data.results;
      } else {
        vehicles = response.data as any[];
      }
  
      // Extract VIN and display name from the new format
      return vehicles.map(vehicle => ({
        vin: vehicle.vin,
        display_name: vehicle.last_state?.vehicle_state?.vehicle_name || vehicle.display_name || `Vehicle ${vehicle.vin.slice(-6)}`
      }));
    }, {
      maxRetries: 2, // Account list is fairly stable
      baseDelay: 1500
    });
  }

• src/query-optimizer.ts:264-270 (helper)

  Natural language query parser recognizes vehicle list queries and maps to 'get_vehicles' operation.

  if (lowerQuery.includes('vehicle') && (lowerQuery.includes('list') || lowerQuery.includes('all'))) {
    return {
      operation: 'get_vehicles',
      parameters: {},
      confidence: 0.8
    };
  }