"Nearly all failures in decision making come from making decisions in isolation.
Pressure does something predictable: it narrows attention. In a triage meeting where every option has a cost, that narrowing turns into a demand for certainty you cannot honestly provide.
When the boundary is unwritten, people optimize for what is legible and defensible, not for what is true. That is how you get busywork and brittle systems. If you cannot describe the boundary simply, the boundary will not survive escalation and reorgs. A clean stop line prevents optimism from keeping a failing bet alive long after the evidence turns.
State the non-goal and the boundary that keeps scope from turning into a rewrite. That is how you stay decisive without pretending to be certain. Keep it short enough to remember under stress.