get_property_price_index

Instructions

Implementation Reference

• src/modules/realestate.ts:155-244 (handler)

  Handler function for the get_property_price_index tool.

  async function handleGetPropertyPriceIndex(
    args: Record<string, unknown>
  ): Promise<string> {
    const rawType = typeof args.type === "string" ? args.type.trim().toLowerCase() : "all";
    const rawFrom = typeof args.from === "string" ? args.from.trim() : undefined;
    const rawTo = typeof args.to === "string" ? args.to.trim() : undefined;
  
    const validTypes = ["all", "houses", "apartments"];
    if (!validTypes.includes(rawType)) {
      throw new Error(`Invalid type "${rawType}". Must be one of: all, houses, apartments`);
    }
  
    // Filter by from/to
    let data = [...SWRPI_ALL_DATA];
  
    if (rawFrom) {
      const parsed = parseQuarter(rawFrom);
      if (!parsed) throw new Error(`Invalid from value: "${rawFrom}". Use format like "2020Q1" or "2020"`);
      data = data.filter(
        (d) => d.year > parsed.year || (d.year === parsed.year && d.quarter >= parsed.quarter)
      );
    }
  
    if (rawTo) {
      const parsed = parseQuarter(rawTo);
      if (!parsed) throw new Error(`Invalid to value: "${rawTo}". Use format like "2024Q4" or "2024"`);
      data = data.filter(
        (d) => d.year < parsed.year || (d.year === parsed.year && d.quarter <= parsed.quarter)
      );
    }
  
    if (data.length === 0) {
      throw new Error("No data available for the specified period range");
    }
  
    // Build series based on type
    const series = data.map((d) => {
      const entry: Record<string, unknown> = { period: d.period };
      if (rawType === "all") entry.index = d.index_all;
      else if (rawType === "houses") entry.index = d.index_houses;
      else entry.index = d.index_apartments;
      return entry;
    });
  
    // Trend: compare latest to previous year same quarter
    const latest = data[data.length - 1];
    const prevYear = data.find(
      (d) => d.year === latest.year - 1 && d.quarter === latest.quarter
    );
  
    let latestIndex: number;
    let prevIndex: number | undefined;
    if (rawType === "all") {
      latestIndex = latest.index_all;
      prevIndex = prevYear?.index_all;
    } else if (rawType === "houses") {
      latestIndex = latest.index_houses;
      prevIndex = prevYear?.index_houses;
    } else {
      latestIndex = latest.index_apartments;
      prevIndex = prevYear?.index_apartments;
    }
  
    const trend =
      prevIndex !== undefined
        ? {
            change_yoy: parseFloat((((latestIndex - prevIndex) / prevIndex) * 100).toFixed(2)),
            change_yoy_label: `${latest.period} vs ${quarterToLabel(latest.year - 1, latest.quarter)}`,
          }
        : null;
  
    // Reference: fetch dataset metadata from CKAN for the source URL
    const datasetUrl = `https://opendata.swiss/en/dataset/${SWRPI_DATASET_ID}`;
  
    return JSON.stringify({
      type: rawType,
      baseline: "Q4 2019 = 100",
      from: data[0].period,
      to: data[data.length - 1].period,
      latest_index: latestIndex,
      latest_period: latest.period,
      data_points: series.length,
      series,
      trend,
      note: "Swiss Residential Property Price Index (SWRPI). Baseline Q4 2019 = 100.",
      source: "Federal Statistical Office (BFS) — Swiss Residential Property Price Index (SWRPI)",
      source_url: datasetUrl,
      dataset_id: SWRPI_DATASET_ID,
    });
  }

• src/modules/realestate.ts:399-428 (schema)

  Schema definition for the get_property_price_index tool.

  {
    name: "get_property_price_index",
    description:
      "Get the Swiss Residential Property Price Index (SWRPI) — official BFS data. " +
      "Baseline Q4 2019 = 100. Returns quarterly index values tracking Swiss property prices " +
      "since 2009. Covers all properties, single-family houses, and apartments separately.",
    inputSchema: {
      type: "object",
      properties: {
        type: {
          type: "string",
          description:
            'Property type to filter by: "all" (combined index), "houses" (single-family), ' +
            '"apartments" (condominiums/flats). Defaults to "all".',
        },
        from: {
          type: "string",
          description:
            'Start period (inclusive). Format: "2020Q1", "2020-Q1", or just "2020". ' +
            "Defaults to earliest available (2009-Q4).",
        },
        to: {
          type: "string",
          description:
            'End period (inclusive). Format: "2024Q4", "2024-Q4", or just "2024". ' +
            "Defaults to latest available.",
        },
      },
    },
  },

• src/modules/realestate.ts:478-484 (registration)

  Dispatcher for the real estate tools, including registration of get_property_price_index.

  export async function handleRealEstate(
    name: string,
    args: Record<string, unknown>
  ): Promise<string> {
    switch (name) {
      case "get_property_price_index":
        return handleGetPropertyPriceIndex(args);