From “worked once” to “works every time”
The gap between a demo and a competition run is the difference between a capability existing and a capability being reachable.
The most expensive defect I keep meeting is the capability that looks finished — correct code, passing tests — and does nothing on the vehicle, because nothing that runs actually calls it. A module written, reviewed, merged, and never reached.
A capability is only real if the path to it is.
The fix is not more code. It is a decision made at write time: this module is either imported by something that runs, or it carries a written reason naming the consumer it is waiting for. There is no third state, and the moment you write it is the only moment anyone knows whether a consumer exists.
Injection-verify your guards
A test that has never failed against a real defect is not a guard — it is decoration. So we break the guard deliberately, watch it fail, and restore it. If it does not fail when the thing it protects is broken, it was never protecting anything.
Reliability is not a feeling you get from green checkmarks. It is what remains after you have tried, on purpose, to make each check lie to you.