What problem does it solve? Writing and reviewing EVM smart contracts without a systematic method misses the vulnerability classes that actually lose funds: reentrancy in all four shapes, proxy storage collisions, silent cast truncation, oracle manipulation, and non-standard ERC-20 behavior. This Skill provides verified, version-specific rules and workflows for developing, reviewing, upgrading, and testing Solidity contracts defensively. ## Core Features & Use Cases - Contract review workflow: Inventory entry points, run Slither first, walk vulnerability classes by realized losses, and ship every finding with a Foundry test that fails before the fix and passes after. - Upgrade safety checks: Diff storage layouts with forge inspect, verify _authorizeUpgrade gating and _disableInitializers(), and fork-test the real proxy before upgrading. - Foundry testing discipline: Handler-based invariant suites, bound-based fuzzing, precise revert assertions, and reading the per-selector calls/reverts table as evidence. - Use Case: Given a vault contract holding user ETH, produce a review that identifies the reentrancy drain, the read-only reentrancy affecting integrators, and the missing access control, each with a reproducing Foundry test. ## Quick Start Ask the agent to review your Solidity contract for security issues before deployment, and it will apply the vulnerability checklist, run Slither, and write reproducing Foundry tests for each finding.