The 60-page handover PDF is a tradition that produces shelf-ware. The docs that get used are short, live next to the code, and answer three questions: how do I run it, how do I deploy it, and what breaks most often.
The README is the contract. Setup in under ten steps, environment variables listed with examples, and the one command that proves the system works. If a new developer can't get it running in an afternoon, the docs failed, not the developer.
A short OPERATIONS.md covers the rest: where the logs live, how backups run, how to restore, and the three failure modes you've seen. Real incidents beat hypothetical ones.
Write docs as you build, not at the end. The decisions are fresh, the gotchas are current, and the handover session becomes a walkthrough instead of an autopsy.
