GitHub Copilot and friends tend to shine in languages with rich static types - think Rust or Scala. Why? The compiler does the heavy lifting. It flags mistakes fast, keeps structure tight, and gives the AI sharper signals to riff on.
But drop that agent into a sprawling legacy repo, and cracks show. With no access to old design choices or full context, these tools hit comprehension debt - and generate fixes that no human would trust in prod.
