SKILL: solidity-dev

Purpose

Design and implement secure Solidity smart contracts with explicit security controls, tests, and deterministic build/validation steps.

When to Use

• The task requires a new contract (ERC-20/721/1155) or extending an existing one.
• You need secure patterns (access control, pausable, reentrancy protection).
• You need Hardhat/Foundry test scaffolding.

Inputs

• contract_spec (required, object|string): requirements, roles, invariants, events.
• standard (optional, enum: erc20|erc721|erc1155|custom).
• tooling (optional, enum: hardhat|foundry).
• security_constraints (optional, string[]): e.g., “no upgradeability”, “pausable required”.
• deployment_target (optional, string): local/testnet/mainnet (mainnet requires explicit user approval).

Steps

1. Clarify requirements:
   • roles and permissions
   • asset flows
   • invariants (must always hold)
2. Select proven libraries (prefer OpenZeppelin) and decide if upgradeability is required.
3. Implement contract with explicit patterns:
   • access control (Ownable/AccessControl)
   • checks-effects-interactions for external calls
   • ReentrancyGuard where applicable
   • Pausable for emergency stop if appropriate
4. Add events for critical state changes.
5. Write tests that assert invariants and failure modes.
6. Validate:
   • compile
   • run tests
   • run static checks when available (slither/foundry invariants) without blocking if tooling is absent.

Validation

• No privileged method lacks access control.
• External calls are safe (reentrancy considered).
• Arithmetic uses Solidity 0.8+ safety; no unsafe casts without justification.
• Tests cover:
  • happy path
  • access control denial
  • edge conditions
  • reentrancy-sensitive flows (where relevant)

Output

• Contract source files (paths)
• Test files (paths)
• Build/validate commands
• Security notes (assumptions + risk areas)

Safety Rules

• Never embed private keys, mnemonics, or RPC secrets in code.
• Never deploy to mainnet without explicit user confirmation and a dry-run on testnet/local first.
• Avoid custom crypto unless unavoidable.
• Reject “guaranteed profit” or manipulative tokenomics requirements.

Example

Input:

• standard: erc20
• contract_spec: “Mintable by MINTER_ROLE, pausable transfers, capped supply.”

Output:

• contracts/MyToken.sol, test/MyToken.t.sol (or Hardhat equivalent)
• validation: forge test (or npx hardhat test)