Yeah, tests. You need tests for everything and the tests + API needs to be carefully reviewed. Technically, the implementation need not be read at all. Just API

Yeah, tests. You need tests for everything and the tests + API needs to be carefully reviewed. Technically, the implementation need not be read at all. Just APIs, boundaries, and tests. You need unit tests, mutation tests (tests for your tests), integration tests, and end-to-end tests. You also need to design the system to be broken up into small submodules, which is how software should be written anyway. You push all side-effects right to the edge, and then test the core extensively. Nobody needs to understand the whole. They only need to understand each submodule, which is easy. And then, how they interact, in which case you only care about the API and contract garauntees, not the implementation. Realistically, this is how pre-AI software engineering worked, too. Or how it should generally work. Nobody can read or understand a 10 million line codebase. So to ensure you don’t break shit, you need the submodules, orchestration, and tests.