National Parks MCP Server

Instructions

Implementation Reference

• src/handlers/getCampgrounds.ts:6-44 (handler)

  The primary handler function for the 'getCampgrounds' tool. It validates input, calls the NPS API client to fetch campgrounds data, formats the response, groups by park, and returns a JSON-formatted text content response.
  export async function getCampgroundsHandler(args: z.infer<typeof GetCampgroundsSchema>) { // Set default limit if not provided or if it exceeds maximum const limit = args.limit ? Math.min(args.limit, 50) : 10; // Format the request parameters const requestParams = { limit, ...args }; const response = await npsApiClient.getCampgrounds(requestParams); // Format the response for better readability by the AI const formattedCampgrounds = formatCampgroundData(response.data); // Group campgrounds by park code for better organization const campgroundsByPark: { [key: string]: any[] } = {}; formattedCampgrounds.forEach(campground => { if (!campgroundsByPark[campground.parkCode]) { campgroundsByPark[campground.parkCode] = []; } campgroundsByPark[campground.parkCode].push(campground); }); const result = { total: parseInt(response.total), limit: parseInt(response.limit), start: parseInt(response.start), campgrounds: formattedCampgrounds, campgroundsByPark: campgroundsByPark }; return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] }; }
• src/schemas.ts:34-39 (schema)

  Zod schema defining the input parameters for the getCampgrounds tool, including optional filters for parkCode, limit, start, and search query.
  export const GetCampgroundsSchema = z.object({ parkCode: z.string().optional().describe('Filter campgrounds by park code (e.g., "yose" for Yosemite). Multiple parks can be comma-separated (e.g., "yose,grca").'), limit: z.number().optional().describe('Maximum number of campgrounds to return (default: 10, max: 50)'), start: z.number().optional().describe('Start position for results (useful for pagination)'), q: z.string().optional().describe('Search term to filter campgrounds by name or description') });
• src/server.ts:63-67 (registration)

  Tool registration in the ListTools response, defining the name, description, and input schema for getCampgrounds.
  { name: "getCampgrounds", description: "Get information about available campgrounds and their amenities", inputSchema: zodToJsonSchema(GetCampgroundsSchema), },
• src/server.ts:105-108 (registration)

  Dispatch handler in the CallToolRequest switch statement that parses arguments with the schema and calls the getCampgroundsHandler.
  case "getCampgrounds": { const args = GetCampgroundsSchema.parse(request.params.arguments); return await getCampgroundsHandler(args); }
• src/utils/npsApiClient.ts:445-453 (helper)

  Helper method in NPS API client that makes the HTTP request to the NPS campgrounds endpoint and returns the raw API response.
  async getCampgrounds(params: CampgroundQueryParams = {}): Promise<NPSResponse<CampgroundData>> { try { const response = await this.api.get('/campgrounds', { params }); return response.data; } catch (error) { console.error('Error fetching campgrounds data:', error); throw error; } }