Circle CCTP MCP Server

A Model Context Protocol (MCP) server that enables seamless USDC-only transactions across multiple blockchains using Circle's Cross-Chain Transfer Protocol (CCTP) v2 and Circle Paymaster. Perfect for AI agents that need to handle USDC transfers without worrying about native gas tokens.

🌟 Circle-Powered Features

🔄 Cross-Chain USDC Transfers (CCTP v2)

• Native USDC: Real USDC transfers, not bridges or wrapped tokens
• 8 Testnets Supported: Ethereum, Base, Arbitrum, Avalanche, Sonic, Linea, Worldchain, Unichain Sepolia
• Fast & Standard Modes: Choose your transfer speed
• AI-Friendly: Simple tool calls for complex cross-chain operations

⛽ Gasless USDC Transactions (Circle Paymaster)

• Pay Gas with USDC: No ETH required for transactions
• Two Versions Available:
  • v0.8 (Recommended): EIP-7702 Smart Accounts, 7 testnets
  • v0.7 (Legacy): Circle Smart Accounts, Arbitrum Sepolia only
• Perfect UX: Recipients receive USDC without paying gas fees
• Account Abstraction: Modern wallet infrastructure built-in

🚀 Quick Start

Claude Desktop Configuration

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "circle-cctp": {
      "command": "npx",
      "args": ["-y", "circle-cctp-mcp-server"],
      "env": {
        "PRIVATE_KEY": "0x..."
      }
    }
  }
}

🛠 Circle CCTP Tools

Core Cross-Chain Transfer Tools

cctp_cross_chain_transfer

Transfer USDC between chains using Circle's native protocol

// Transfer 25 USDC from Ethereum to Base
{
  "name": "cctp_cross_chain_transfer",
  "arguments": {
    "fromChainId": 11155111,    // Ethereum Sepolia
    "toChainId": 84532,         // Base Sepolia
    "recipientAddress": "0x742d35Cc6654B3B5B2F214fB3E6dC8b5b1234567",
    "amount": "25.0",
    "transferType": "fast"      // or "standard"
  }
}

Parameters:

• fromChainId: Source chain ID
• toChainId: Destination chain ID
• amount: USDC amount (e.g., "10.5")
• recipientAddress: Destination address
• transferType: "fast" or "standard" (optional)

get_usdc_balance_cctp

Check USDC balance on any supported chain

// Check balance on Arbitrum Sepolia
{
  "name": "get_usdc_balance_cctp",
  "arguments": {
    "chainId": 421614,
    "address": "0x742d35Cc6654B3B5B2F214fB3E6dC8b5b1234567"
  }
}

get_supported_chains_cctp

Get all chains supported by Circle CCTP

Returns list of 8 supported testnets with chain IDs and domain mappings.

get_domain_mappings_cctp

Get Circle domain mappings for CCTP protocol

⛽ Circle Paymaster Tools

Gasless Transaction Tools

paymaster_get_account_address

Get your Circle Smart Account address for funding

// Get EIP-7702 account address for Base Sepolia
{
  "name": "paymaster_get_account_address",
  "arguments": {
    "chainId": 84532,
    "version": "v0.8"          // or "v0.7" for legacy
  }
}

What it returns:

• Smart Account address
• Current USDC balance
• Funding instructions
• Account type (EIP-7702 vs Circle Smart Account)

paymaster_check_balance

Check USDC balance in your Smart Account

// Check balance in Smart Account
{
  "name": "paymaster_check_balance",
  "arguments": {
    "chainId": 421614,
    "version": "v0.8"
  }
}

paymaster_send_usdc

Send gasless USDC transfers (recipient pays zero gas)

// Send 5 USDC gaslessly
{
  "name": "paymaster_send_usdc",
  "arguments": {
    "chainId": 421614,
    "recipientAddress": "0x8879318091671ba1274e751f8cDEF76bb37eb3eD",
    "amount": "5.0",
    "version": "v0.8"
  }
}

Flow:

1. User pays gas in USDC (not ETH)
2. Recipient receives USDC without paying any gas
3. Perfect onboarding experience

paymaster_get_supported_chains

Get chains supported by Circle Paymaster

// Get v0.8 supported chains (7 testnets)
{
  "name": "paymaster_get_supported_chains",
  "arguments": {
    "version": "v0.8"
  }
}

🌐 Supported Networks

CCTP v2 Cross-Chain Transfers

Circle Paymaster v0.8 (EIP-7702 Smart Accounts)

Circle Paymaster v0.7 (Legacy)

💬 Natural Language Usage

In Claude Desktop

"Transfer 10 USDC from Ethereum Sepolia to Base Sepolia"

"Send 5 USDC gaslessly to 0x123... on Arbitrum Sepolia using Circle Paymaster"

"What's my USDC balance on all chains?"

"Get my Circle Smart Account address for Arbitrum Sepolia so I can fund it"

"Check if I can send gasless transactions on Base Sepolia"

🔄 How Circle CCTP Works

Circle's Cross-Chain Transfer Protocol enables native USDC transfers without bridges:

Source Chain          Circle API          Destination Chain
     |                     |                        |
[Burn USDC] ---------> [Attestation] ---------> [Mint USDC]
     |                     |                        |
TokenMessenger         Iris API               MessageTransmitter

Process:

1. Burn: USDC burned on source chain via Token Messenger
2. Attest: Circle's attestation service signs the burn message
3. Mint: Native USDC minted on destination chain

Benefits:

• ✅ Real USDC (not wrapped)
• ✅ 2-5 minute transfers
• ✅ Lower fees than bridges
• ✅ Circle's audited contracts

⛽ How Circle Paymaster Works

Circle Paymaster enables USDC-only transactions where users pay gas in USDC:

User Wallet           Circle Paymaster           Blockchain
     |                        |                        |
[Sign Permit] ----------> [Receive USDC] --------> [Pay Gas in ETH]
     |                        |                        |
[Send UserOp] ----------> [Bundle & Submit] -----> [Execute Transaction]
     |                        |                        |
[Pay 0 ETH] <------------- [Deduct USDC] <--------- [Transaction Success]

Process:

1. EIP-2612 Permit: User signs permit for paymaster to spend USDC
2. User Operation: Transaction bundled with paymaster data
3. Gas Payment: Paymaster pays ETH gas, deducts equivalent USDC
4. Execution: Transaction executes, user never touches ETH

Benefits:

• ✅ Zero ETH required
• ✅ Perfect onboarding UX
• ✅ Recipients pay no gas
• ✅ Multi-chain support

🚀 Getting Started

1. Fund Your Account

For CCTP transfers:

• Fund your EOA with USDC on any supported chain
• Use Circle Faucet

For Paymaster gasless transfers:

# Get your Smart Account address
"Get my Circle Smart Account address for Arbitrum Sepolia"

# Fund it with USDC at https://faucet.circle.com
# Then send gasless transactions!

2. Start Transferring

# Cross-chain transfer
"Send 10 USDC from Base to Arbitrum"

# Gasless transfer  
"Send 5 USDC gaslessly to 0x123... on Base using Circle Paymaster"

💡 Best Practices

1. Use v0.8 Paymaster: Better performance and more chains than v0.7
2. Fund Smart Accounts: Ensure your Circle Smart Account has USDC for gasless transfers
3. Check Balances: Regular balance checks help track transfers
4. Consider Speed: Use "fast" transfers for urgent transactions
5. Test First: Use testnets to familiarize yourself with the tools

🛡️ Security

• Private keys stored locally in .env files
• All transactions signed locally using viem
• Circle's audited smart contracts
• Testnet environments for safe experimentation

🔗 Resources

• Circle CCTP Documentation
• Circle Paymaster Documentation
• Circle Developer Hub
• Model Context Protocol
• USDC Faucet

📝 License

MIT License - see LICENSE file for details.

Made with ❤️ for the Circle ecosystem and AI agent developers who want USDC-only transactions without gas token complexity.