Circle CCTP

Native USDC across chains by burn-and-mint — never wrapped.

CCTP (Cross-Chain Transfer Protocol) is Circle’s canonical way to move USDC between chains: USDC is burned on the source chain and minted natively on the destination — never a wrapped or bridged variant. A-Identity drives it with Circle’s Bridge Kit (CCTPv2), so an agent’s dollars can leave Arc and arrive as real USDC on another chain.

This is the second cross-chain rail alongside Circle Gateway. They solve related problems differently: Gateway moves a unified balance via the Forwarding Service; CCTP is the burn-and-mint primitive underneath native USDC liquidity.

The burn-and-mint lifecycle

1. approve

   The bridge is approved to spend the USDC being moved.

2. burn

   USDC is burned on Arc, emitting a cross-chain message.

3. fetchAttestation

   Circle attests the burn. Because Arc has instant finality, the attestation is reached fast.

4. mint

   Native USDC is minted on the destination chain (Base Sepolia in our demo) — the same dollar, no wrapper.

Verified live on Arc testnet: a 1 USDC transfer ran the full approve → burn → fetchAttestation → mint lifecycle in about 15 seconds, each step a real transaction, minting native USDC on Base Sepolia — on both the local and the live production backend. SDK: @circle-fin/bridge-kit.

Gateway vs CCTP

	Circle Gateway	CCTP
Model	Unified balance + Forwarding Service	Burn-and-mint
Destination gas	None (minted gaslessly)	Standard mint on destination
Best for	Chain-abstracted spending	Canonical native-USDC liquidity
In A-Identity	mcp/src/gateway.ts	mcp/src/cctp.ts

Leaving Arc, the bridged amount must exceed the CCTPv2 max fee — tiny testnet transfers can revert with “Max fee must be less than amount”. The demo defaults to 1 USDC.

Build on Arc

Arc is the primary rail — gas in USDC, sub-second finality. CCTP and Gateway extend it across chains.