Perp dex limits and status (HIP-3)

Risk limits and status of ONE builder-deployed perp dex (HIP-3): total open-interest cap, per-perp OI size cap, max transfer notional, the per-coin OI caps, the coins currently AT their OI cap, and the dex's total net deposit. Send POST /api/perp-dex-limits with the required field dex and pay $0.002 per call over x402 or MPP (there is no free tier). It returns a JSON object with source, dex, totalOiCapUsd, oiSzCapPerPerpUsd, maxTransferNtlUsd and 6 more.

Three keyless reads (perpDexLimits, perpDexStatus, perpsAtOpenInterestCap) in one call.

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/perp-dex-limits \
  -H "Content-Type: application/json" \
  -d '{"dex":"xyz","limit":5}'

Without payment this returns HTTP 402 Payment Required with the exact price for perp-dex-limits; any x402 v2 or MPP client pays it and retries.

Example response

{
  "source": "hyperliquid",
  "dex": "xyz",
  "totalOiCapUsd": 10000000000,
  "oiSzCapPerPerpUsd": 20000000000,
  "maxTransferNtlUsd": 3000000000,
  "totalNetDepositUsd": 1089269477.99,
  "count": 1,
  "totalCoins": 122,
  "coinOiCaps": [
    {
      "coin": "xyz:SP500",
      "oiCapUsd": 1250000000
    }
  ],
  "atOiCap": {
    "count": 0,
    "coins": []
  },
  "fetchedAt": "2026-09-18T12:00:00.000Z"
}

From an MCP client

catalog.call {
  "slug": "perp-dex-limits",
  "params": {
    "dex": "xyz",
    "limit": 5
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for perp-dex-limits; the stdio package pays it from a wallet or from an AGENT402_CREDITS_KEY issued earlier. Local install: npx -y agent402-mcp.

Errors and behavior

• dex is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/perp-dex-limits returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.({ maxAmountPerPayment: "$0.002" }); // refuse any quote above this tool's price
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/perp-dex-limits", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "dex": "xyz",
    "limit": 5
  }),
});

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