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{
  "mcpServers": {
    "stable-docs": {
      "url": "https://docs.stable.xyz/mcp"
    },
    "stable-runtime": {
      "url": "https://runtime.stable.xyz/mcp"
    }
  }
}

claude mcp add stable-docs https://docs.stable.xyz/mcp
claude mcp add stable-runtime https://runtime.stable.xyz/mcp

claude plugin add stable-xyz/agent-skills

# Stable chain context

Stable is a Layer 1 where USDT0 is the native gas token. Fully EVM-compatible.
All standard EVM tools (Hardhat, Foundry, ethers.js, viem) work unchanged once
you adjust three gas fields (see Behavioral differences below).

## Network

| Field           | Mainnet                                  | Testnet                                    |
| :-------------- | :--------------------------------------- | :----------------------------------------- |
| Chain ID        | 988                                      | 2201                                       |
| RPC             | https://rpc.stable.xyz                   | https://rpc.testnet.stable.xyz             |
| Explorer        | https://stablescan.xyz                   | https://testnet.stablescan.xyz             |
| Currency symbol | USDT0                                    | USDT0                                      |

## USDT0 contract addresses

- Mainnet: 0x779ded0c9e1022225f8e0630b35a9b54be713736
- Testnet: 0x78cf24370174180738c5b8e352b6d14c83a6c9a9

## Behavioral differences from Ethereum

1. **Gas token is USDT0, not ETH.** The `value` field in native transfers
   carries USDT0. Fees are denominated in USDT0.
2. **`maxPriorityFeePerGas` is always 0.** No tip-based ordering. Set it
   explicitly to `0n` or validators will reject or ignore tip components.
3. **USDT0 has a dual role**: native asset (18 decimals) AND ERC-20 (6 decimals)
   on the same balance. `address(x).balance` reports 18-decimal wei; 
   `USDT0.balanceOf(x)` reports 6-decimal units. Values may differ by up to
   0.000001 USDT0 due to fractional reconciliation. Never mirror native
   balance in an internal variable; always query at payout time.
4. **Transfer events are emitted for native transfers too.** A single Transfer
   event listener on the USDT0 ERC-20 contract covers both transfer paths.
5. **Single-slot finality (~700ms).** Once a block is committed, it cannot
   be reorged. No need to wait multiple confirmations.
6. **Gas Waiver** lets applications cover gas: user signs with `gasPrice = 0`,
   a governance-registered waiver wraps and submits. Contracts must be on
   the waiver's AllowedTarget policy.
7. **EIP-7702** is supported for delegating an EOA to a contract (type-4 tx).
8. **Precompile addresses**: Bank `0x...1003`, Distribution `0x...0801`,
   Staking `0x...0800`, StableSystem `0x...9999`.

## Common mistakes to avoid

- Copying Ethereum priority-fee constants (2 gwei tips, etc.) — has no effect
  on Stable and can be rejected by wallets.
- Using `ethers.parseUnits(x, 18)` for ERC-20 USDT0 amounts. ERC-20 uses 6
  decimals; native transfers use 18.
- Mirroring native balance in a `uint256 deposited` variable — USDT0
  allowance-based operations (transferFrom, permit) can reduce a contract's
  native balance without invoking its code.
- Sending native or ERC-20 USDT0 to `address(0)` — both revert on Stable.
- Assuming `EXTCODEHASH == 0` means an address is unused. On Stable,
  permit-based approvals can change state without incrementing nonce.
- Writing `value: ethers.parseEther(amount, "ether")` and expecting ETH
  semantics. That transfer sends USDT0.

Use Foundry to scaffold a project called `stable-escrow`. Write a minimal
Escrow contract in Solidity ^0.8.24 with deposit() and withdraw(amount)
functions that transfer USDT0 natively. Use address(this).balance for
solvency checks (never mirror the balance in a uint256). Reject
address(0) recipients. Then produce a deployment command using
`forge create` pointed at Stable testnet (RPC https://rpc.testnet.stable.xyz,
chain ID 2201).

Write a TypeScript script using ethers v6 that sends 0.001 USDT0 natively
from the wallet loaded from PRIVATE_KEY. Use base-fee-only EIP-1559 gas
(maxPriorityFeePerGas = 0n, maxFeePerGas = 2 * baseFeePerGas). Target
Stable testnet. Log the tx hash and a Stablescan explorer URL.

Write a TypeScript script using ethers v6 that:
1. Signs an EIP-7702 authorization delegating my EOA to Multicall3 at
   0xcA11bde05977b3631167028862bE2a173976CA11 on Stable testnet
   (chain ID 2201).
2. Sends a type-4 transaction with authorizationList: [signedAuth],
   to: wallet.address (self-call), and data that invokes aggregate3()
   to batch three USDT0 transfers (100, 200, 150 USDT0 with 6 decimals).
3. Use maxPriorityFeePerGas: 0n.

Write a SubscriptionManager Solidity contract for EIP-7702 delegation on
Stable. It runs on a subscriber's EOA. Expose:
  - subscribe(bytes32 subId, address provider, uint256 amount, uint256 interval)
    callable only when msg.sender == address(this) (subscriber on their own EOA).
  - collect(bytes32 subId) callable only by the registered provider, only
    when block.timestamp >= nextChargeAt; advances nextChargeAt by interval
    and transfers USDT0 to the provider. Use IERC20 USDT0 at the testnet
    address 0x78cf24370174180738c5b8e352b6d14c83a6c9a9.
  - cancelSubscription(bytes32 subId) callable only by the subscriber.
Emit events for SubscriptionCreated, SubscriptionCollected, SubscriptionCancelled.

Write an Express server in TypeScript that exposes GET /weather priced
at $0.001 USDT0 (amount: "1000", 6 decimals) using @x402/express,
@x402/evm/exact/server, and HTTPFacilitatorClient pointed at
https://x402.semanticpay.io/. Use Stable mainnet (CAIP-2 eip155:988,
USDT0 at 0x779Ded0c9e1022225f8E0630b35a9b54bE713736). The handler should
return { weather: "sunny", temperature: 70 }. Read PAY_TO_ADDRESS from
env. Print the configured routes on startup.