> Do current LLM based agents generate code which is easy to change?

Yes, if that's your goal and you take steps to achieve that goal while working with agents.

That means figuring out how to prompt them, providing them good examples (they'll work better in a codebase which is already designed to afford future changes since they imitate existing patterns) and keeping an eye on what they're doing so you can tell them "rewrite that like X" when they produce something bad.

> Once you can ask your agent to change a feature and be 100% sure they won't break other features

That's why I tell them to use red/green TDD: https://simonwillison.net/guides/agentic-engineering-pattern...