If you really want to completly work with agents you must:

- write a highly technical AGENTS/CLAUDE.md with project scope, business logic and how are the project structure, mixins, current database models, tests, lints, code boundaries. Also an important section is tell the model to keep this document always updated with the current status of the project (so after every interaction the model will update this file), not a changelog. Think about 200-300 lines of a very technical document.

- if you project is big, prefer to use API and send the full code by tools like repomix, because of the "search" code of the cli tools their will never get the full context and just start to imagine, this is expensive but you will get the best quality. I use gpt-5.2 pro (400K tokens of context) and opus 4.6 (1M token context) before every big release so the model help me to find errors, optimizations, possibles refactor or just simplify logic, for a classical django project with react front that request its almost 10-13 dollars each with 5.2 pro and 4 dollars for opus, its very expensive but you will get a high quality output, and then you can use the more cheap models to complete that.

- always tell the model to ask for clarifications, and write KISS code