mcp-swiss

Instructions

Implementation Reference

• src/modules/dams.ts:309-360 (handler)

  The handler implementation for the `get_dams_by_canton` tool, which validates the input canton code, fetches its bounding box, and filters dams within that area.

  case "get_dams_by_canton": {
    const canton = args.canton as string;
    if (!canton?.trim()) {
      throw new Error("canton is required (2-letter code, e.g. 'VS', 'GR', 'BE')");
    }
  
    const cantonCode = canton.trim().toUpperCase();
    if (!/^[A-Z]{2}$/.test(cantonCode)) {
      throw new Error("canton must be a 2-letter Swiss canton code (e.g. 'VS', 'GR', 'BE', 'ZH')");
    }
  
    // Get canton bounding box
    const bbox = await fetchCantonBbox(cantonCode);
    if (!bbox) {
      throw new Error(`Unknown canton code: "${cantonCode}". Use standard 2-letter Swiss canton abbreviations (VS, GR, BE, UR, TI, VD, etc.)`);
    }
  
    const [xmin, ymin, xmax, ymax] = bbox;
  
    // Fetch all dams with geometry to filter by canton bbox
    const allDams = await findDams("%", "damname", true);
  
    // Filter dams whose coordinates fall within the canton bbox
    const cantonDams = allDams.filter((dam) => {
      const x = dam.geometry?.x;
      const y = dam.geometry?.y;
      if (x == null || y == null) return false;
      return x >= xmin && x <= xmax && y >= ymin && y <= ymax;
    });
  
    if (!cantonDams.length) {
      return JSON.stringify({
        canton: cantonCode,
        dams: [],
        count: 0,
        message: `No dams found in canton ${cantonCode}. This canton may not have any dams under federal supervision.`,
        source: `${BASE}/find?layer=${DAMS_LAYER}`,
      }, null, 2);
    }
  
    const limited = cantonDams.slice(0, MAX_RESULTS);
    const formatted = limited.map((dam) => formatDamSummary(dam, cantonCode));
  
    const response = {
      canton: cantonCode,
      dams: formatted,
      count: formatted.length,
      total_in_canton: cantonDams.length,
      note: cantonDams.length > MAX_RESULTS
        ? `Showing first ${MAX_RESULTS} of ${cantonDams.length} dams in canton ${cantonCode}.`
        : undefined,
      source: `${BASE}/find?layer=${DAMS_LAYER}`,

• src/modules/dams.ts:216-231 (schema)

  The tool definition and input schema for `get_dams_by_canton`.

  {
    name: "get_dams_by_canton",
    description:
      "List all Swiss dams under federal supervision in a given canton. Returns up to 20 dams with basic details. Data source: Swiss Federal Office of Energy (SFOE) via swisstopo BGDI.",
    inputSchema: {
      type: "object",
      required: ["canton"],
      properties: {
        canton: {
          type: "string",
          description:
            "Swiss canton 2-letter abbreviation code (e.g. 'VS' for Valais, 'GR' for Graubünden, 'BE' for Bern, 'UR' for Uri, 'TI' for Ticino, 'VD' for Vaud).",
        },
      },
    },
  },