eBird MCP Server

Instructions

Implementation Reference

• src/index.ts:111-122 (handler)

  The handler function that implements the core logic for the 'get_species_observations' tool. It prepares query parameters, makes an API request to the eBird endpoint for recent species observations in a region, and returns the result as formatted JSON text content.

  async (args) => {
    const params: Record<string, string | number | boolean> = {
      back: args.back,
      hotspot: args.hotspot,
      includeProvisional: args.include_provisional,
      sppLocale: args.spp_locale,
    };
    if (args.max_results) params.maxResults = args.max_results;
  
    const result = await makeRequest(`/data/obs/${args.region_code}/recent/${args.species_code}`, params);
    return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] };
  }

• src/index.ts:102-110 (schema)

  Zod schema defining the input parameters and their validation rules, descriptions, and defaults for the 'get_species_observations' tool.

  {
    region_code: z.string().describe("Country, subnational1, subnational2, or location code"),
    species_code: z.string().describe("eBird species code (e.g., 'cangoo' for Canada Goose, 'barswa' for Barn Swallow)"),
    back: z.number().min(1).max(30).default(14).describe("Number of days back to fetch"),
    hotspot: z.boolean().default(false).describe("Only fetch from hotspots"),
    include_provisional: z.boolean().default(false).describe("Include unreviewed observations"),
    max_results: z.number().min(1).max(10000).optional().describe("Maximum observations to return"),
    spp_locale: z.string().default("en").describe("Language for common names"),
  },

• src/index.ts:99-123 (registration)

  The complete registration of the 'get_species_observations' tool with the McpServer instance using server.tool(), including name, description, input schema, and handler function.

  server.tool(
    "get_species_observations",
    "Get recent observations of a specific species in a region.",
    {
      region_code: z.string().describe("Country, subnational1, subnational2, or location code"),
      species_code: z.string().describe("eBird species code (e.g., 'cangoo' for Canada Goose, 'barswa' for Barn Swallow)"),
      back: z.number().min(1).max(30).default(14).describe("Number of days back to fetch"),
      hotspot: z.boolean().default(false).describe("Only fetch from hotspots"),
      include_provisional: z.boolean().default(false).describe("Include unreviewed observations"),
      max_results: z.number().min(1).max(10000).optional().describe("Maximum observations to return"),
      spp_locale: z.string().default("en").describe("Language for common names"),
    },
    async (args) => {
      const params: Record<string, string | number | boolean> = {
        back: args.back,
        hotspot: args.hotspot,
        includeProvisional: args.include_provisional,
        sppLocale: args.spp_locale,
      };
      if (args.max_results) params.maxResults = args.max_results;
  
      const result = await makeRequest(`/data/obs/${args.region_code}/recent/${args.species_code}`, params);
      return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] };
    }
  );

• src/index.ts:19-36 (helper)

  Shared helper utility function used by the 'get_species_observations' handler (and other tools) to construct and make authenticated HTTP requests to the eBird API, handling URL parameters, authentication, error checking, and JSON parsing.

  async function makeRequest(endpoint: string, params: Record<string, string | number | boolean> = {}): Promise<unknown> {
    const url = new URL(`${BASE_URL}${endpoint}`);
    Object.entries(params).forEach(([key, value]) => {
      if (value !== undefined && value !== null) {
        url.searchParams.append(key, String(value));
      }
    });
  
    const response = await fetch(url.toString(), {
      headers: { "X-eBirdApiToken": API_KEY! },
    });
  
    if (!response.ok) {
      throw new Error(`eBird API error: ${response.status} ${response.statusText}`);
    }
  
    return response.json();
  }