name: solidity description: "Best practices for secure, gas-efficient Solidity smart contract development and Web3 frontend integration. Use when writing or reviewing Solidity contracts, hardening against reentrancy and access-control bugs, optimizing gas usage, setting up Hardhat/Foundry testing and static analysis, or wiring a React frontend to wallets, providers, and on-chain transactions."

Solidity

This skill covers best practices for Solidity smart contract development, including security patterns, gas optimization, testing/tooling, and integrating contracts with a Web3 React frontend.

Core Principles

• Cut the fluff. Code or detailed explanations only
• Maintain brevity while prioritizing accuracy and depth
• Answer first, explain later when needed

Code Structure & Security

• Use explicit visibility modifiers and NatSpec documentation
• Apply function modifiers to reduce redundancy
• Follow naming conventions:
  • CamelCase for contracts
  • PascalCase for interfaces (prefix with "I")
• Implement Interface Segregation Principle
• Use proxy patterns for upgradeable contracts
• Emit comprehensive events for state changes
• Follow Checks-Effects-Interactions pattern against reentrancy

Security Best Practices

• Use OpenZeppelin's AccessControl for permissions
• Require Solidity 0.8.0+ for overflow/underflow protection
• Use Pausable pattern for circuit breakers
• Implement ReentrancyGuard for additional protection
• Use SafeERC20 for token interactions
• Employ pull-over-push payment patterns
• Implement timelocks and multisig controls for sensitive operations

Gas Optimization

• Optimize gas consumption (deployment and runtime)
• Use immutable variables for constructor-set values
• Use custom errors instead of revert strings
• Pack storage variables efficiently
• Use appropriate data types

Tools & Analysis

• Integrate Slither and Mythril for static analysis
• Leverage Hardhat's testing and development environment
• Implement robust CI/CD pipelines
• Use pre-commit linting tools

Advanced Patterns

• Chainlink VRF for randomness
• Strategic assembly use with extensive documentation
• State machine patterns for complex logic
• ERC20Snapshot, ERC20Permit, and ERC20Votes for specialized tokens

Testing & Quality

• Comprehensive unit, integration, and end-to-end testing
• Property-based testing approaches
• High coverage targets
• Regular security audits

Web3 Frontend Integration

• Keep frontend code that talks to contracts type-safe and explicit — generate TypeScript types from ABIs (e.g. via TypeChain or wagmi/viem codegen) rather than hand-writing contract call signatures
• Treat wallet connection, chain/network state, and transaction status as explicit, typed state (connected/connecting/wrong-network/error), not implicit booleans
• Surface transaction lifecycle clearly in the UI: submitted, pending confirmation, confirmed, reverted — never assume a submitted transaction succeeded
• Validate and simulate transactions (e.g. eth_call/gas estimation) before prompting the user to sign, to catch reverts early
• Never trust client-side reads of contract state for authorization decisions — always re-verify on-chain in the contract itself
• Handle provider/RPC failures and user rejection of signature requests as expected, recoverable error states