Polymarket Thin Book Detection

Instructions

Implementation Reference

• src/tools/pm_micro.ts:89-138 (handler)

  Handler function for the pm_micro_thin tool. Calls /api/v1/pm/micro/thin with threshold and limit params, returns API results or error.

  server.registerTool(
    "pm_micro_thin",
    {
      title: "Polymarket Thin Book Detection",
      description:
        "Detect markets with thin order books that may be susceptible to slippage or " +
        "manipulation. Shows markets below a liquidity threshold with spread metrics. " +
        "Cost: $0.005 per query. Source: Polymarket order book analysis.",
      inputSchema: {
        threshold: z
          .number()
          .optional()
          .describe("Liquidity threshold in USD (markets below this are flagged)"),
        limit: z
          .number()
          .int()
          .min(1)
          .max(100)
          .optional()
          .describe("Maximum results (default 25)"),
      },
    },
    async ({ threshold, limit }) => {
      const res = await apiGet<PmMicroQueryResponse>("/api/v1/pm/micro/thin", {
        threshold: threshold ?? 50,
        limit: limit ?? 25,
      });
  
      if (!res.ok) {
        return {
          content: [
            {
              type: "text" as const,
              text: `API error (${res.status}): ${JSON.stringify(res.data)}`,
            },
          ],
          isError: true,
        };
      }
  
      const { count, data } = res.data;
      const warn = stalenessWarning(res);
      const summary = `${warn}Found ${count} thin book market(s).`;
      const json = JSON.stringify(data, null, 2);
  
      return {
        content: [{ type: "text" as const, text: `${summary}\n\n${json}` }],
      };
    },
  );

• src/tools/pm_micro.ts:97-109 (schema)

  Input schema for pm_micro_thin: optional threshold (number) and limit (int 1-100).

  inputSchema: {
    threshold: z
      .number()
      .optional()
      .describe("Liquidity threshold in USD (markets below this are flagged)"),
    limit: z
      .number()
      .int()
      .min(1)
      .max(100)
      .optional()
      .describe("Maximum results (default 25)"),
  },

• src/index.ts:58-58 (registration)

  Registration call in the main index.ts that wires up all pm_micro tools including pm_micro_thin.

  registerPmMicroTools(server);

• src/tools/pm_micro.ts:28-28 (registration)

  The registration function that calls server.registerTool for pm_micro_thin (and other pm_micro tools).

  export function registerPmMicroTools(server: McpServer): void {

• src/client.ts:44-76 (helper)

  The apiGet helper used by the handler to make HTTP GET requests to the Verilex API, including staleness detection.

  export async function apiGet<T = unknown>(
    path: string,
    params?: Record<string, string | number | undefined>,
  ): Promise<ApiResponse<T>> {
    const url = buildUrl(path, params);
  
    const headers: Record<string, string> = {
      Accept: "application/json",
      "User-Agent": "verilex-mcp-server/0.1.0",
    };
  
    // Forward x402 payment token if present in env (for paid endpoints)
    const paymentToken = process.env.VERILEX_PAYMENT_TOKEN;
    if (paymentToken) {
      headers["X-Payment-Token"] = paymentToken;
    }
  
    const res = await fetch(url, { headers });
    const data = (await res.json()) as T;
  
    const stale = res.headers.get("X-Data-Stale");
    const lastUpdated = res.headers.get("X-Data-Last-Updated");
    const ageSeconds = res.headers.get("X-Data-Age-Seconds");
  
    return {
      ok: res.ok,
      status: res.status,
      data,
      stale: stale === "true",
      lastUpdated: lastUpdated ?? undefined,
      ageSeconds: ageSeconds ? Number(ageSeconds) : undefined,
    };
  }

• src/client.ts:35-41 (helper)

  The stalenessWarning helper used by the handler to append stale data warnings to the output.

  export function stalenessWarning(res: ApiResponse): string {
    if (!res.stale) return "";
    const parts = ["[STALE DATA]"];
    if (res.lastUpdated) parts.push(`Last updated: ${res.lastUpdated}`);
    if (res.ageSeconds != null) parts.push(`Age: ${res.ageSeconds}s`);
    return parts.join(" ") + "\n\n";
  }