Most handoffs fail because too much context stays unwritten. The code may run, but the reasons behind it live in meeting notes, private memories, and old Slack threads nobody can find.
Systems the next team can actually run
Cleverness only its author can operate is a dead end, however elegant. So the why gets written down along with the what: decisions, trade-offs, and the roads not taken. Conventions stay boring enough that a new engineer stops being surprised within a week. And every part of the system has a name attached, someone who can speak for it.
The handoff is the deliverable
Runbooks that have been run. Architecture decisions on record. Onboarding measured in days, not folklore. When we leave, the system should be easier for your team to run than when we arrived.