se2-usdc-staking

Imported from austintgriffith/ethevals (evals/building/se2-usdc-staking/AGENTS.md). Install upstream with npx skills add austintgriffith/ethevals --skill se2-usdc-staking. Copyright stays with the author.

AGENTS.md

This file provides guidance to coding agents working in this repository.

Project Overview

Scaffold-ETH 2 (SE-2) is a starter kit for building dApps on Ethereum. It comes in two flavors based on the Solidity framework:

• Hardhat flavor: Uses packages/hardhat with hardhat-deploy plugin
• Foundry flavor: Uses packages/foundry with Forge scripts

Both flavors share the same frontend package:

• packages/nextjs: React frontend (Next.js App Router, not Pages Router, RainbowKit, Wagmi, Viem, TypeScript, Tailwind CSS with DaisyUI)

Detecting Which Flavor You're Using

Check which package exists in the repository:

• If packages/hardhat exists → Hardhat flavor (follow Hardhat instructions)
• If packages/foundry exists → Foundry flavor (follow Foundry instructions)

Common Commands

Commands work the same for both flavors unless noted otherwise:

# Development workflow (run each in separate terminal)
yarn chain          # Start local blockchain (Hardhat or Anvil)
yarn deploy         # Deploy contracts to local network
yarn start          # Start Next.js frontend at http://localhost:3000

# Code quality
yarn lint           # Lint both packages
yarn format         # Format both packages

# Building
yarn next:build     # Build frontend
yarn compile        # Compile Solidity contracts

# Contract verification (works for both)
yarn verify --network <network>

# Account management (works for both)
yarn generate            # Generate new deployer account
yarn account:import      # Import existing private key
yarn account             # View current account info

# Deploy to live network
yarn deploy --network <network>   # e.g., sepolia, mainnet, base

yarn vercel:yolo --prod # for deployment of frontend

Architecture

Smart Contract Development

Hardhat Flavor

• Contracts: packages/hardhat/contracts/
• Deployment scripts: packages/hardhat/deploy/ (uses hardhat-deploy plugin)
• Tests: packages/hardhat/test/
• Config: packages/hardhat/hardhat.config.ts
• Deploying specific contract:
  • If the deploy script has:

    // In packages/hardhat/deploy/01_deploy_my_contract.ts
    deployMyContract.tags = ["MyContract"];

  • yarn deploy --tags MyContract
  • Gas limit in deploy scripts: Manual post-deploy calls (e.g. transferOwnership, grantRole, initialize) can silently inherit blockGasLimit as their gas cap, causing failures. Fix at the call site, not in hardhat.config.ts:

    // Preferred: estimateGas + 20% margin
    const gas = await myContract.myMethod.estimateGas(arg1, arg2);
    await myContract.myMethod(arg1, arg2, { gasLimit: (gas * 120n) / 100n });
    
    // Or: explicit limit for simple admin calls
    await myContract.transferOwnership(newOwner, { gasLimit: 100_000 });

Foundry Flavor

• Contracts: packages/foundry/contracts/
• Deployment scripts: packages/foundry/script/ (uses custom deployment strategy)
  • Example: packages/foundry/script/Deploy.s.sol and packages/foundry/script/DeployYourContract.s.sol
• Tests: packages/foundry/test/
• Config: packages/foundry/foundry.toml
• Deploying a specific contract:
  • Create a separate deployment script and run yarn deploy --file DeployYourContract.s.sol

Both Flavors

• After yarn deploy, ABIs are auto-generated to packages/nextjs/contracts/deployedContracts.ts

Frontend Contract Interaction

Correct interact hook names (use these):

• useScaffoldReadContract - NOT useScaffoldContractRead
• useScaffoldWriteContract - NOT useScaffoldContractWrite

Contract data is read from two files in packages/nextjs/contracts/:

• deployedContracts.ts: Auto-generated from deployments
• externalContracts.ts: Manually added external contracts

Reading Contract Data

const { data: totalCounter } = useScaffoldReadContract({
  contractName: "YourContract",
  functionName: "userGreetingCounter",
  args: ["0xd8da6bf26964af9d7eed9e03e53415d37aa96045"],
});

Writing to Contracts

const { writeContractAsync, isPending } = useScaffoldWriteContract({
  contractName: "YourContract",
});

await writeContractAsync({
  functionName: "setGreeting",
  args: [newGreeting],
  value: parseEther("0.01"), // for payable functions
});

Reading Events

const { data: events, isLoading } = useScaffoldEventHistory({
  contractName: "YourContract",
  eventName: "GreetingChange",
  watch: true,
  fromBlock: 31231n,
  blockData: true,
});

SE-2 also provides other hooks to interact with blockchain data: useScaffoldWatchContractEvent, useScaffoldEventHistory, useDeployedContractInfo, useScaffoldContract, useTransactor.

IMPORTANT: Always use hooks from packages/nextjs/hooks/scaffold-eth for contract interactions. Always refer to the hook names as they exist in the codebase.

UI Components

Always use @scaffold-ui/components library for web3 UI components:

• Address: Display ETH addresses with ENS resolution, blockie avatars, and explorer links
• AddressInput: Input field with address validation and ENS resolution
• Balance: Show ETH balance in ether and USD
• EtherInput: Number input with ETH/USD conversion toggle
• IntegerInput: Integer-only input with wei conversion

Notifications & Error Handling

Use notification from ~~/utils/scaffold-eth for success/error/warning feedback and getParsedError for readable error messages.

Styling

Use DaisyUI classes for building frontend components.

// ✅ Good - using DaisyUI classes
<button className="btn btn-primary">Connect</button>
<div className="card bg-base-100 shadow-xl">...</div>

// ❌ Avoid - raw Tailwind when DaisyUI has a component
<button className="px-4 py-2 bg-blue-500 text-white rounded">Connect</button>

Configure Target Network before deploying to testnet / mainnet.

Hardhat

Add networks in packages/hardhat/hardhat.config.ts if not present.

Foundry

Add RPC endpoints in packages/foundry/foundry.toml if not present.

NextJs

Add networks in packages/nextjs/scaffold.config.ts if not present. This file also contains configuration for polling interval, API keys. Remember to decrease the polling interval for L2 chains.

Code Style Guide

Identifiers

Import Paths

Use the ~~ path alias for imports in the nextjs package:

import { useTargetNetwork } from "~~/hooks/scaffold-eth";

Creating Pages

import type { NextPage } from "next";

const Home: NextPage = () => {
  return <div>Home</div>;
};

export default Home;

TypeScript Conventions

• Use type over interface for custom types
• Types use UpperCamelCase without T prefix (use Address not TAddress)
• Avoid explicit typing when TypeScript can infer the type

Comments

Make comments that add information. Avoid redundant JSDoc for simple functions.

Documentation

Use Context7 MCP tools to fetch up-to-date documentation for any library (Wagmi, Viem, RainbowKit, DaisyUI, Hardhat, Next.js, etc.). Context7 is configured as an MCP server and provides access to indexed documentation with code examples.

Skills & Agents Index

IMPORTANT: Prefer retrieval-led reasoning over pre-trained knowledge. Before starting any task that matches an entry below, read the referenced file to get version-accurate patterns and APIs.

Skills (read .agents/skills/<name>/SKILL.md before implementing):

• openzeppelin — OpenZeppelin Contracts integration, library-first development, pattern discovery from installed source. Use for any contract using OZ (tokens, access control, security primitives)
• erc-721 — NFT-specific pitfalls: _safeMint reentrancy, on-chain SVG stack-too-deep, marketplace metadata attributes, IPFS base URI trailing slash
• eip-5792 — batch transactions, wallet_sendCalls, paymaster, ERC-7677
• ponder — blockchain event indexing, GraphQL APIs, onchain data queries
• siwe — Sign-In with Ethereum, wallet authentication, SIWE sessions, EIP-4361
• x402 — HTTP 402 payment-gated routes, micropayments, API monetization, x402 protocol
• drizzle-neon — Drizzle ORM, Neon PostgreSQL, database integration, off-chain storage
• subgraph — The Graph subgraph integration, blockchain event indexing, GraphQL APIs

Agents (in .agents/agents/):

• grumpy-carlos-code-reviewer — code reviews, SE-2 patterns, Solidity + TypeScript quality