name: foundry
description: "Foundry toolkit for Solidity development. Forge testing, Cast interactions, Anvil local node, deployment scripts. Use when building or testing smart contracts."
metadata:
openclaw:
emoji: "🔨"

Foundry

Blazing fast Solidity development toolkit. Forge (test), Cast (interact), Anvil (local node), Chisel (REPL).

Quick Start

forge init my-project
cd my-project
forge build
forge test

Project Structure

my-project/
├── src/           # Contracts
├── test/          # Tests (Solidity)
├── script/        # Deployment scripts
├── lib/           # Dependencies (git submodules)
└── foundry.toml   # Configuration

foundry.toml (Base Config)

[profile.default]
src = "src"
out = "out"
libs = ["lib"]
solc = "0.8.24"
optimizer = true
optimizer_runs = 200

[rpc_endpoints]
base = "${BASE_RPC_URL}"
base_sepolia = "https://sepolia.base.org"

[etherscan]
base = { key = "${BASESCAN_API_KEY}", url = "https://api.basescan.org/api" }
base_sepolia = { key = "${BASESCAN_API_KEY}", url = "https://api-sepolia.basescan.org/api" }

Testing

// test/MyContract.t.sol
pragma solidity ^0.8.20;
import "forge-std/Test.sol";
import "../src/MyContract.sol";

contract MyContractTest is Test {
    MyContract c;

    function setUp() public {
        c = new MyContract();
    }

    function test_basicFunction() public {
        assertEq(c.getValue(), 42);
    }

    function testFuzz_setValue(uint256 x) public {
        c.setValue(x);
        assertEq(c.getValue(), x);
    }

    function testFail_unauthorized() public {
        vm.prank(address(0xdead));
        c.adminOnly(); // Should revert
    }
}

Key Cheatcodes

Fork Testing

# Test against live Base state
forge test --fork-url https://mainnet.base.org

Deployment

// script/Deploy.s.sol
pragma solidity ^0.8.20;
import "forge-std/Script.sol";
import "../src/MyContract.sol";

contract Deploy is Script {
    function run() external {
        vm.startBroadcast(vm.envUint("PRIVATE_KEY"));
        new MyContract();
        vm.stopBroadcast();
    }
}

# Deploy to Base Sepolia
forge script script/Deploy.s.sol --rpc-url base_sepolia --broadcast --verify

# Deploy to Base mainnet
forge script script/Deploy.s.sol --rpc-url base --broadcast --verify

Cast (CLI Interaction)

# Read contract
cast call $CONTRACT "balanceOf(address)" $ADDR --rpc-url base

# Send transaction
cast send $CONTRACT "transfer(address,uint256)" $TO $AMT --rpc-url base --private-key $PK

# Get balance
cast balance $ADDR --rpc-url base

# Decode calldata
cast decode-calldata "transfer(address,uint256)" $CALLDATA

Gas Optimization

forge test --gas-report
forge snapshot          # Save gas snapshot
forge snapshot --diff   # Compare with previous

References

• references/full-reference.md — Complete Foundry guide with detailed examples, advanced patterns, invariant testing, and deployment workflows

Cross-References

• solidity: Language patterns
• smart-contract-security: Security testing
• testing-patterns: Test methodology
• deployment-ops: Production deployment