Why not write tests with AI, too? Since using LLMs as coding assistants, my codebases have much more thorough documentation, testing and code coverage.

Don't start when you're already in a buggy dead-end. Test-driven development with LLMs should be done right from the start.

Also keep the code modular so it is easy to include the correct context. Fine-grained git commits. Feature-branches.

All the tools that help teams of humans of varying levels of expertise work together.