Can Claude Audit Smart Contracts? Zero-Shot Vulnerability Detection Across Five SWC Classes

This article evaluates Claude Sonnet 4.6 on five vulnerable Solidity contracts from the SmartBugs Curated benchmark using a zero-shot auditing setup. Claude successfully identified all five primary vulnerability classes — including reentrancy, integer underflow, tx.origin misuse, timestamp manipulation, and unchecked send — while also surfacing additional valid findings across the contracts. The analysis focuses not only on detection accuracy, but on Claude’s tendency to consistently overestimate severity, raising questions about how LLMs should be positioned alongside tools like Slither and Mythril within real-world smart contract auditing workflows.