The end state of a live system is not that it trades. It is that it can be stopped, and that stopping it is a decision someone made with a number. Everything else in this subject exists to make that state reachable.
About 1 min of reading
Enforce a ceiling and prove the stop
Write the ceiling in the executor
Before you run it, say out loud what it will print. Then open the answer.
Attempt a book that breaches it
Before you run it, say out loud what it will print. Then open the answer.
Name the cause of the stop
Before you run it, say out loud what it will print. Then open the answer.
The executor is the only component that acts. A ceiling enforced anywhere else is a request, and requests are not obeyed by bugs.
A system that refuses more than it trades. That is the state where a claim is a number, and it is the state most systems never reach.
A ceiling that the system enforces is a stop that happens. A ceiling that is remembered is a ceiling that will be exceeded.
Input list, test suite, last scores, open cases. The shape of a shippable system does not change with the subject.
Costs, data, and execution are changed first. A model changed on top of unknown costs is a model that cannot be judged.
Each one is defined here on this site. Open the entry for the full definition and the other words it points at.