Alpaca MCP Server

Implementation Reference

• index.ts:65-87 (handler)

  The main handler function for the 'get-stock-bars' tool. It fetches historical stock bars from the Alpaca API, batching symbols (up to 2000 per batch) and handling pagination with page tokens.

  export async function getStockBars({ symbols, start, end, timeframe }: { symbols: string[]; start: string; end: string; timeframe: string }) {
    try {
      const result: { bars: Record<string, unknown> } = { bars: {} };
      for (const batch of getBatches(symbols, 2000)) {
        let pageToken: string | undefined;
        do {
          const params: Record<string, unknown> = { timeframe, limit: 10000, start, end, symbols: batch.join(",") };
          if (pageToken) params.page_token = pageToken;
          const resp = await request<{ bars: Record<string, unknown>; next_page_token?: string }>({
            base: process.env.ALPACA_ENDPOINT!,
            path: "/v2/stocks/bars",
            params,
          });
          Object.assign(result.bars, resp.bars);
          pageToken = resp.next_page_token;
        } while (pageToken);
      }
      return { content: [{ type: "text", text: JSON.stringify(result) }] as any };
    } catch (err: any) {
      debug("get-stock-bars error", err);
      return { content: [{ type: "text", text: `Error fetching stock bars: ${err.message}` }] as any, isError: true };
    }
  }

• index.ts:138-147 (registration)

  Registers the 'get-stock-bars' tool with the MCP server, including the input schema (using Zod) and the handler function.

  server.tool(
    "get-stock-bars",
    {
      symbols: z.array(z.string()),
      start: z.string(),
      end: z.string(),
      timeframe: z.string(),
    },
    getStockBars
  );

• index.ts:140-145 (schema)

  Zod schema defining the input parameters for the 'get-stock-bars' tool: symbols (array of strings), start (string), end (string), timeframe (string).

  {
    symbols: z.array(z.string()),
    start: z.string(),
    end: z.string(),
    timeframe: z.string(),
  },

• index.ts:42-46 (helper)

  Helper function to split an array into batches of a given size, used in getStockBars to batch symbols for API requests (limit 2000).

  function getBatches<T>(arr: T[], size: number): T[][] {
    const batches: T[][] = [];
    for (let i = 0; i < arr.length; i += size) batches.push(arr.slice(i, i + size));
    return batches;
  }