I use 3 AI's (Claude, GPT and Gemini) to review each other's design plans and implementation on the same code base. Each often catches problems the others miss.

I try to make sure the architecture docs of the code base are refreshed regularly based on recent changes, so it's easier for humans and AI agents to make sense of the code.

I also regularly stop all other developments and just focus on auditing the code base with these AI's to make sure they are secure, robust, clean, and well structured and well tested -- some refactoring would be needed most of the time, and it's well worth it.

With this approach, nowadays I often merge code from AI without completely understanding what it's doing, but seems the code has been working so far. :)