Price History Link (Keepa)

Instructions

Implementation Reference

• src/index.ts:331-350 (handler)

  The handler function for the price_history_link tool. Extracts ASIN from input, builds Keepa URL via keepaUrl(), and returns the result.

    async (params) => {
      const asin = extractAsinFromUrl(params.asin_or_url.trim());
      if (!asin) {
        return {
          content: [
            {
              type: "text",
              text:
                "Error: Could not extract ASIN. Pass a 10-character ASIN or an amazon.in URL containing /dp/<ASIN>.",
            },
          ],
        };
      }
      const output = { asin, price_history_url: keepaUrl(asin) };
      return {
        content: [{ type: "text", text: JSON.stringify(output, null, 2) }],
        structuredContent: output,
      };
    }
  );

• src/index.ts:136-144 (schema)

  Zod schema for price_history_link input: requires a single 'asin_or_url' string (10-2048 chars).

  const PriceHistoryInputSchema = z
    .object({
      asin_or_url: z
        .string()
        .min(10)
        .max(2048)
        .describe("ASIN or amazon.in URL — Keepa link is built for the amazon.in domain"),
    })
    .strict();

• src/index.ts:307-350 (registration)

  Registration of the 'price_history_link' tool on the MCP server with input schema and annotations.

  server.registerTool(
    "price_history_link",
    {
      title: "Price History Link (Keepa)",
      description: `Build a Keepa.com price-history URL for an amazon.in ASIN. No network call.
  
  Keepa renders historical price charts in the browser using the format keepa.com/#!product/12-<ASIN>, where 12 is the amazon.in domain code. This tool is offline — just a deterministic URL builder.
  
  Args:
    - asin_or_url (string): plain ASIN or amazon.in URL containing /dp/<ASIN>
  
  Returns: JSON
    {
      "asin": string,
      "price_history_url": string
    }`,
      inputSchema: PriceHistoryInputSchema.shape,
      annotations: {
        readOnlyHint: true,
        destructiveHint: false,
        idempotentHint: true,
        openWorldHint: false,
      },
    },
    async (params) => {
      const asin = extractAsinFromUrl(params.asin_or_url.trim());
      if (!asin) {
        return {
          content: [
            {
              type: "text",
              text:
                "Error: Could not extract ASIN. Pass a 10-character ASIN or an amazon.in URL containing /dp/<ASIN>.",
            },
          ],
        };
      }
      const output = { asin, price_history_url: keepaUrl(asin) };
      return {
        content: [{ type: "text", text: JSON.stringify(output, null, 2) }],
        structuredContent: output,
      };
    }
  );

• src/parse.ts:20-22 (helper)

  The keepaUrl() helper that builds the Keepa.com price-history URL using KEEPA_DOMAIN_CODE (12 for amazon.in).

  export function keepaUrl(asin: string): string {
    return `https://keepa.com/#!product/${KEEPA_DOMAIN_CODE}-${asin}`;
  }

• src/parse.ts:41-45 (helper)

  The extractAsinFromUrl() helper that extracts a 10-char ASIN from plain input or amazon.in URL.

  export function extractAsinFromUrl(input: string): string | undefined {
    if (ASIN_REGEX.test(input)) return input;
    const match = input.match(ASIN_FROM_URL_REGEX);
    return match?.[1]?.toUpperCase();
  }