This repository has been modified and simplified from the Chainlink examples repository.

This repository contains a collection of Foundry scripts designed to simplify and show deployment of a CMTAT token with CCIP contracts.

Find a list of available tutorials on the Chainlink documentation: Cross-Chain Token (CCT) Tutorials.

See also ccip-cct-starter

This project has not undergone an audit and is provided as-is without any warranties.

Technical Specifications

• Deploy a CMTAT token on two testnet blockchains (e.g., Sepolia and Avalanche Fuji).
• Bridge tokens between them using Chainlink CCIP.
• The CMTAT token already implements the Cross-Chain Token standard.
• Provide guidelines and details for the main steps involved.

Repository Preparation

Note: The default project layout in foundry.toml has been overridden to src = "lib/cmta/contracts". To build the project, follow these steps:

1. Clone the repository.
2. Run forge install and npm install.
3. Navigate to the lib/cmta directory and run npm install and git submodule update.
4. Run forge build.

Prerequisites

This guide assumes you are already familiar with Solidity, Foundry, and Chainlink CCIP. You should also have native tokens (e.g., ETH on Sepolia and AVAX on Fuji) and LINK tokens on both chains.

Main Steps

0. Optional: Start local Anvil servers for both chains: npm run start-anvil:sepolia and npm run start-anvil:fuji.
1. Deploy the token on both chains: npm run exec:broadcast -- deploy:token <sepolia/fuji>
2. Deploy the token pool on both chains: npm run exec:broadcast -- deploy:token-pool <sepolia|fuji>
3. Claim the admin role on both chains: npm run exec:broadcast -- claim-admin <sepolia|fuji>
4. Accept the admin role on both chains: npm run exec:broadcast -- accept-admin <sepolia|fuji>
5. Set the token pool on both chains: npm run exec:broadcast -- set-token-pool <sepolia|fuji>
6. Apply chain updates on both chains: npm run exec:broadcast -- apply-chain-updates <sepolia|fuji> <destinationChainSelector>
7. Mint tokens on a chain: npm run exec:broadcast -- mint <sepolia|fuji> <amount>
8. Transfer tokens between chains: npm run exec:broadcast -- transfer <sepolia|fuji> <amount> <native|link> <destinationChainSelector>

Quick Overview of Each Step

0. Before broadcasting any transactions, it is a best practice to run the scripts locally to ensure everything works as expected. You can start two forked Anvil servers (one for Sepolia and one for Fuji) for local testing.
1. First, deploy the CMTATStandalone token contract on both chains. We use this version because it includes the getCCIPAdmin function, which simplifies the admin claiming process.
2. After deploying the token, deploy the BurnMintTokenPool contract on both chains.
3. On CMTAT, set the CCIP admin address
4. Claim the admin role for the token pool. This will allow you to configure the necessary settings for bridging.
5. Complete the process by accepting the admin role.
6. Wire up the token pool to the token contract by setting the pool address on the token contract.
7. Link the chains by applying the chain updates on both token pools.
8. On CMTAT, grant the minter role to the pool contract
9. Mint new tokens to an address.
10. Bridge the tokens from a source chain to a destination chain.
    • Approve the router contract to spend tokens on your behalf
    • Call ccipSenderon the router contract

Note

Some steps are interchangeable, others must be done in order. For example, the CCIP admin role must be set in the CMTAT before the admin role can be claimed on the token registry contract.

Artifacts

• Deployments
• Sepolia to Fuji Transfer | Fuji to Sepolia Transfer

Example

Transfer from Fuji to Sepolia

Contract

Here the list of contracts called

	Avalanche Fuji Address	Deploy
CMTAT	0x0eB9B06137B6087D0e9423203473f9e0B58D59Ea	CMTAT deployer
Pool contract	0xD83909F43D934fbDC3D62d91285B518009c8d7Ee	CMTAT deployer
Token Admin registry	0xA92053a4a3922084d992fD2835bdBa4caC6877e6	Chainlink
Router	0xF694E193200268f9a4868e4Aa017A0118C9a8177	Chainlink

Step

Step	Description	Target contract	Function	Script	Note	Transaction [Avalanche Fuji]
Deployment
1	Deploy CMTAT token	-	-	DeployToken.s.sol	-	https://testnet.snowtrace.io/tx/0xaa1f8ecad4e21bd1563a8ed56b4d7f4026b0a1ba52331c88cd04f91fcd89634a?chainid=43113
2	Deploy CCIP pool (e.g. BurnMintTokenPool)	-	-	DeployBurnMintTokenPool.s.sol	-	https://testnet.snowtrace.io/tx/0xbca532f461ad1248ca1bf8d8a417c4bc4a19625b7dfbf6f9a9e5e15197e3f755?chainid=43113
CMTAT configuration
3	Set the CCIP admin	CMTAT	setCCIPAdmin(address newAdmin)	DeployToken.s.sol	-	https://testnet.snowtrace.io/tx/0xd3ff7e6e899c2deaa27b4a4a0bf14b5d47f5420df1f85c59eb9af0ff13c22f93?chainid=43113
Token Admin Registry configuration
4	Claim the admin role on both chains	TokenAdminRegistry	registerAdminViaGetCCIPAdmin(address token)	ClaimAdmin.s.sol	-	https://testnet.snowtrace.io/tx/0x66f921c979c2ed5d3bafeffbfbb9c9d317941289b6587a35f4b2f24e649c8f22?chainid=43113
5	Accept the admin role on both chains	TokenAdminRegistry	acceptAdminRole(address localToken)	AcceptAdminRole.s.sol	-	https://testnet.snowtrace.io/tx/0xbb5eb3cfe5cc4ab3183bfe3eb4336c0201ee6734b87955662f0b391989e94120?chainid=43113
6	Set Token Pool on both chain	TokenAdminRegistry	setPool(address localToken, address pool)	SetPool.s.sol	localToken is the CMTAT address	https://testnet.snowtrace.io/address/0xA92053a4a3922084d992fD2835bdBa4caC6877e6
Pool configuration
7	Apply chain updates on both chains / configure supported blockchain	BurnMintTokenPool	applyChainUpdates(uint64[] remoteChainSelectorsToRemove, (uint64 remoteChainSelector, bytes[] remotePoolAddresses, bytes remoteTokenAddress, (bool isEnabled, uint128 capacity, uint128 rate) outboundRateLimiterConfig, (bool isEnabled, uint128 capacity, uint128 rate) inboundRateLimiterConfig)[] chainsToAdd)	ApplyChainUpdates.s.sol	-	https://testnet.snowtrace.io/tx/0x267ce681ebefc2895a7d5d0c0d8437a8206ad00d3752559b1710c4e084341cd4?chainid=43113
CMTAT configuration
8	Grant the minter role to the CCIP pool	CMTAT	grantRole(bytes32 role, address account)	-	accountis the CCIP pool address	https://testnet.snowtrace.io/tx/0xd5e543bfce1f00d76dc15b6fab670e04bd46435b1b2b9ad59854e3061df89b3d?chainid=43113
9	Mint new tokens	CMTAT	mint(address account, uint256 value)	MintTokens.s.sol	-	https://testnet.snowtrace.io/tx/0xacc1858294c5cbfda83f034ecb60d4911584413dcd0c3ff379421d3086ef0df0?chainid=43113
Cross-chain Transfer
10	Approve router to spend token on your behalf	CMTAT	ERC-20 approve(address spender, uint256 value)	TransferTokens.s.sol	spenderis the CCIP pool	https://testnet.snowtrace.io/tx/0x625c683b1946cef2db3a30001325846f04bbacaeed76cb177f7a283c9410f774?chainid=43113
11	Transfer tokens by calling ccipSendon the router contract	router	ccipSend(uint64 destinationChainSelector, (bytes receiver, bytes data, (address token, uint256 amount)[] tokenAmounts, address feeToken, bytes extraArgs) message) payable returns (bytes32)	TransferTokens.s.sol	-	https://testnet.snowtrace.io/tx/0x7d9458696b9e0e7c67072bd2cc6802226f05316f216fcec88a39c2322359734d?chainid=43113 https://sepolia.etherscan.io/tx/0x43e500140c7331b03373318c45b85cb8defca51f13b32861f5b03b54c4b7963b

Schema

Here is a schema explaining the transfer from the source chain:

And on the destination chain

You can find more information on the process on the chainlink documentation

Additional Resources

A detailed bridging tutorial from Chainlink can be found here.