StarkGate Bridge MCP

MCP server for StarkGate bridge operations between Ethereum L1 and Starknet L2.

Features

• Bridge ETH and ERC20 tokens (USDC, USDT, WBTC, STRK) from Ethereum L1 to Starknet L2
• Bridge ETH and ERC20 tokens from Starknet L2 to Ethereum L1
• Automatic ERC20 token approval handling
• Token balance and allowance verification
• Secure environment variable-based configuration
• No private keys exposed in tool schemas

Installation

pnpm install
pnpm build

Configuration

Create a .env file based on .env.example:

cp .env.example .env

Required Environment Variables

For Starknet L2 Operations:

• STARKNET_RPC_URL: Your Starknet RPC endpoint
• STARKNET_PRIVATE_KEY: Your Starknet account private key
• STARKNET_ACCOUNT_ADDRESS: Your Starknet account address

For Ethereum L1 Operations:

• ETHEREUM_RPC_URL: Your Ethereum RPC endpoint
• ETHEREUM_PRIVATE_KEY: Your Ethereum wallet private key

Available Tools

bridge_l1_to_l2

Bridge ETH or ERC20 tokens from Ethereum L1 to Starknet L2.

Parameters:

• l1chain (string): The L1 chain to bridge from (e.g., "ethereum")
• toAddress (string): The Starknet address to receive the funds
• amount (string): The amount to bridge (in token units, e.g., "0.001" for ETH or "1.0" for USDC)
• symbol (string): Token symbol (ETH, USDC, USDT, WBTC, STRK)

Supported Tokens:

• ETH (18 decimals)
• USDC (6 decimals)
• USDT (6 decimals)
• WBTC (8 decimals)
• STRK (18 decimals)

Example (ETH):

{
  "l1chain": "ethereum",
  "toAddress": "0x01fbe320049F84A38FbcB21B4Ae1a4aab89e4aB3c825d38d35202Ee873439E7D",
  "amount": "0.001",
  "symbol": "ETH"
}

Example (USDC):

{
  "l1chain": "ethereum",
  "toAddress": "0x01fbe320049F84A38FbcB21B4Ae1a4aab89e4aB3c825d38d35202Ee873439E7D",
  "amount": "10.0",
  "symbol": "USDC"
}

Note: For ERC20 tokens, the bridge will automatically:

1. Check your token balance
2. Check current allowance for the bridge contract
3. Approve the bridge to spend tokens if needed (requires 1 transaction)
4. Execute the bridge deposit (requires 1 transaction)

bridge_l2_to_l1

Bridge ETH or ERC20 tokens from Starknet L2 to Ethereum L1.

Parameters:

• l1chain (string): The L1 chain to bridge to (e.g., "ethereum")
• toAddress (string): The Ethereum address to receive the funds
• amount (string): The amount to withdraw (in token units, e.g., "0.001" for ETH or "1.0" for USDC)
• symbol (string): Token symbol (ETH, USDC, USDT, WBTC, STRK)

Supported Tokens:

• ETH (18 decimals)
• USDC (6 decimals)
• USDT (6 decimals)
• WBTC (8 decimals)
• STRK (18 decimals)

Example (ETH):

{
  "l1chain": "ethereum",
  "toAddress": "0x8283a06f328eff7d505f475b0930260058066388",
  "amount": "0.001",
  "symbol": "ETH"
}

Example (USDC):

{
  "l1chain": "ethereum",
  "toAddress": "0x8283a06f328eff7d505f475b0930260058066388",
  "amount": "10.0",
  "symbol": "USDC"
}

Note: L2 to L1 withdrawals typically take 4-12 hours to finalize on Ethereum due to Starknet's withdrawal mechanism.

Security Notes

• Never commit your .env file to version control
• Private keys are loaded from environment variables only
• No sensitive data is exposed in tool schemas or logs
• Uses onchainWrite pattern from @kasarlabs/ask-starknet-core

Development

# Build the project
pnpm build

# Clean build artifacts
pnpm clean

# Start the MCP server
pnpm start

Architecture

This MCP follows the same pattern as other MCPs in the ask-starknet project:

• Tools: Bridge operation functions in src/tools/bridgeTools.ts
• Schemas: Zod schemas for input validation in src/schemas/
• Utils: Environment configuration helpers in src/lib/utils.ts
• Main: MCP server setup in src/index.ts

License

MIT