A tool that does not know this codebase’s conventions

Suggestions that are idiomatic for the language and wrong for this application, which is the most expensive kind of wrong.

// suggested, and idiomatic PHP
public function getTotal(): float
{
    return $this->total / 100;
}

// this codebase, since 2019: money is minor units in
// an integer, and a float total is the bug we spent a
// quarter removing.

// suggested, and idiomatic Laravel
$order = Order::find($id);
// this codebase: repositories, and Order is a domain
// object rather than a model.

Both suggestions are what most PHP looks like, which is exactly why they are dangerous — they read as correct to a reviewer who is skimming. The mitigation that worked was a conventions file the tool reads, which improved the second case substantially and the first case not at all.