StableGuard

Note on Testnet Choice
Due to time constraints and persistent difficulties in obtaining testnet tokens for Xlayer (despite repeated efforts to contact the team), we have deployed StableGuard on Arc Testnet for this demo. The Xlayer deployment remains under active development, and StableGuard is designed as a multichain CCTP agent—once Xlayer is fully accessible, we will extend the deployment to include it alongside other chains.

Uniswap v4 Hook LP-Protection ASP — built for the OKX.AI Genesis Hackathon

StableGuard protects uniswap pools from impermanent loss and inventory skew during agent-driven, yield-seeking trading. The dynamic fee curve is the product: fees stay low while the pool is calm, and rise automatically as the hook actively defends it. A circuit breaker blocks trades that would push the pool past a safe skew threshold. A lightweight off-chain API exposes this protection status so other agents can check a pool's live risk before routing a swap through it gated via x402 payment.

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Why

Agents increasingly compete for yield across stablecoin pools, and that trading pressure can quietly skew a pool's inventory and expose LPs to impermanent loss. StableGuard makes that risk visible and priced in real time, rather than something LPs only discover after the fact.

Solution

A Uniswap v4 hook on X Layer that:.

1. Tracks pool skew live, on-chain, per swap.
2. Moves the swap fee through three tiers as skew rises — calm, elevated, defensive — so the cost of trading against the pool's balance scales automatically with the risk that trade adds.
3. Hard-blocks trades that would push skew past a safety threshold, via a circuit breaker.
4. Exposes all of this through a stateless off-chain API, so agents can check a pool's live protection status before they submit a swap — not just discover the cost after the fact.
5. Lets agents swap in without a separate on-chain approval step, via a Permit2-based router — matching the gasless-approval pattern the Uniswap Trade API itself uses.

The dynamic fee curve is the product: low fee when calm, higher fee when the hook is actively defending the pool.

How it works

1. Skew tracking — the hook maintains a rolling, decayed skew value per pool, updated on every swap.
2. Dynamic fee tiers — the fee automatically moves between three tiers based on current skew:
   • Calm — 0.01%
   • Elevated — 0.05%
   • Defensive — 0.30%
3. Circuit breaker — a trade projected to push skew past a hard threshold is reverted before it executes.
4. Protection status API — agents call GET /protection-status/:poolId to see the current skew, fee tier, whether the circuit breaker is armed, and the maximum additional skew that's still safe — before they submit a swap.

Architecture

Component	Role	Stack
StableGuardHook.sol	beforeSwap (fee tiering + circuit breaker), afterSwap (skew commit)	Solidity, Foundry, Uniswap v4
MockUSD.sol	Two mintable ERC20s standing in for USDC/USDT on testnet	Solidity
ASP API	Stateless service exposing live protection status	NestJS, ethers.js
Deployment	X Layer (contracts) + Render (API)	Foundry, Docker

Component	Address / Link	Description
StableGuard Hook	0x0B46218C3FA54CC0f1E058016bc4a1f51DCB40C0	Core hook contract implementing the StableGuard logic
PoolManager	0x74efFA1DfA6582e835917cDA5c4932a5dd0e5295	Uniswap V4 PoolManager instance managing the pool
MOCK_USDX	0xfE99b51a3D62363e2C55cc229351997d4771e08a	Mock USDX token contract
MOCK_USDY	0xCD4C3F60FcdeAB580b74A366c31e449716e20Cc9	Mock USDY token contract
Pool ID	0xb6734893c2e5094909ae79428a84e29be959cf7008f30dc4620073b3c5924d91	Unique identifier for the deployed pool
Web Interface	stableguard-r2fz.onrender.com	Frontend application for interacting with StableGuard

API Endpoints

Base URL: https://stableguard-r2fz.onrender.com

Method	Endpoint	Description	Auth
GET	/health	Service health check	None
GET	/protection-status	Protection status for the default demo pool (or specify ?poolId=...)	None
GET	/protection-status/:poolId	Protection status for a specific pool	None
POST	/simulate-trade	Simulate a swap (body: { poolId?, amountSpecified, zeroForOne })	x402‑gated if PAID_MODE=true

Example Requests

# Health check
curl https://stableguard-r2fz.onrender.com/health

# Default pool status
curl https://stableguard-r2fz.onrender.com/protection-status

# Specific pool by path
curl https://stableguard-r2fz.onrender.com/protection-status/0xb6734893c2e5094909ae79428a84e29be959cf7008f30dc4620073b3c5924d91

Example Responses

Health check:

{"status":"ok","service":"stableguard-asp"}

Protection status (pool):

{
  "poolId": "0xb6734893c2e5094909ae79428a84e29be959cf7008f30dc4620073b3c5924d91",
  "netSkew": "0",
  "tier": "calm",
  "currentFeeBps": 1,
  "circuitBreakerArmed": false,
  "maxSafeAdditionalSkew": "300000000000000000",
  "recommendation": "SAFE_TO_SWAP",
  "fetchedAtBlock": 51903459,
  "staleAfterSeconds": 12
}

Known simplifications

• The circuit breaker currently reverts oversized trades rather than partially filling them in-hook. The API's maxSafeAdditionalSkew field lets agents size trades safely in advance; true in-hook partial-fill is the natural next iteration.
• Skew is tracked with a simplified magnitude/direction proxy rather than exact post-trade reserve math — sufficient for tiering and the breaker, tightenable later with direct pool state reads.

Status

Built and submitted for the OKX.AI Genesis Hackathon as a free Agent-to-MCP (A2MCP) service — payment SDK with x402 under develeopment.

License

MIT