Develop with AI

Set up MCP servers, agent skills, and plain-text docs so AI editors and coding agents can build on Stable directly.

Stable provides MCP servers, agent skills, and plain-text documentation files so AI editors and coding agents can work with Stable directly. This page covers how to wire each piece into your workflow, a copy-pasteable context block for non-MCP AI tools, and starter prompts for common tasks.

MCP servers

Stable runs two MCP servers. Docs MCP searches this docs site for concepts, guides, code snippets, and contract references. Runtime MCP interacts with the Stable chain for balance queries, transaction simulation, and execution.

Both servers can be added to any MCP-compatible client.

Cursor

Open your MCP configuration file and add:

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

Restart Cursor. Verify by asking: “How do I send USDT0 on Stable?”

Claude Code

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

Verify by asking: “Search Stable docs for Gas Waiver integration steps.”

Agent skills

Agent skills are predefined workflows that combine Docs MCP and Runtime MCP. When you ask an AI to perform a task like “send 100 USDT0 to three addresses,” the skill handles the full sequence: look up the relevant docs, resolve addresses and parameters, check balances, simulate the transaction, and execute after approval.

Skills are available as a Claude Code plugin.

Install

claude plugin add stable-xyz/agent-skills

Or install from the Claude Code marketplace.

For the full skill definitions and source, see the agent-skills repository.

Plain-text docs

For AI tools that do not support MCP, Stable documentation is available as static text files.

File	URL	Content
llms.txt	https://docs.stable.xyz/llms.txt	Page index with titles and descriptions
llms-full.txt	https://docs.stable.xyz/llms-full.txt	Full documentation in a single file

These files are static snapshots. For the most current content, use Docs MCP.

Cursor

1. Go to Settings > Features > Docs.
2. Select Add and enter https://docs.stable.xyz/llms-full.txt.
3. Reference in chat with @Stable.

Other tools

Download llms-full.txt and include it in your project context or system prompt.

Stable context block

Paste this at the top of any AI chat or system prompt. It gives the model everything it needs to generate correct Stable code on the first attempt.

# 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.

Starter prompts

Copy any of these into your AI editor after loading the context block above.

Deploy a contract

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).

Send USDT0

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.

Set up EIP-7702 delegation

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.

Build a subscription contract

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.

Build an x402 pay-per-call API

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.

Next recommended

Paying with MCP server

Wrap a paid API as an MCP tool so AI clients can call and pay for it.

Quick start

Pair the AI context with a first-transaction run in five minutes.

Difference from Ethereum

Deep-dive on the gas and USDT0 semantics in the context block.