Security · Intermediate

AI smart contract audit: what automated auditing catches, what it misses, and how to use it well

How AI-assisted smart contract auditing works, the vulnerability classes it reliably finds, where it falls short, and how to combine it with static analysis and human review.

Three kinds of automated review exist. Static analysis pattern-matches source or bytecode against known bad shapes. Dynamic analysis executes the contract, often with fuzzed inputs, and watches for violations. AI review reads the code the way a reviewer would, reasoning about intent, and is good at the things pattern matching is bad at, and vice versa.

What AI auditing reliably catches

• Reentrancy, including cross-function variants that simple pattern matchers miss.
• Missing or inconsistent access control (a mint anyone can call).
• Unchecked external call results and unsafe low-level calls.
• Mismatches between a function's name or comment and what it does.
• Obvious logic errors: wrong comparison direction, off-by-one in loops, state updated after a call.

What it misses

• Economic attacks that depend on market conditions or multi-block sequences.
• Problems that only appear in the interaction between several contracts it cannot see.
• Anything requiring knowledge of your business rules that is not in the code.
• Novel vulnerability classes with no precedent in its training.

Using it well

1. Run it early and often, on every compile, not once at the end. Cheap feedback changes how you write.
2. Fix everything it flags as high risk before spending human review time.
3. Read its explanations. The reasoning is often more useful than the verdict.
4. Feed it context: a comment explaining an invariant lets it check the invariant.
5. Pair it with execution: run the contract in a real EVM and confirm the fixes behave.

Monsmith's audit

Monsmith runs an AI-assisted audit in the browser on every contract, scores overall risk, lists findings by severity with the line in question, and proposes concrete fixes. It is free and needs no account. It is designed to be the first pass that clears mechanical issues, so that a human audit, which anything holding real value should still get, can concentrate on judgement.