This seam sits between the seat that decides what a task is (the Planner, across its plan and dispatch acts) and the seat that runs it (the Operator). It exists because running a task and re-scoping one look adjacent from the run button, and they are not: the Operator operates what the Planner already made ready, and the moment the work needs its scope, criteria, or approach changed, that is the Planner's again — never the Operator's to edit in flight.
What crosses, downward — a task the Planner has made dispatchable: its Issue cut, its dependencies merged, no conflicting sibling open, its brief renderable. The Planner's dispatch act is what turns a planned Issue into a startable run; the Operator picks it up from there and operates it through the controller.
What crosses, upward — a scope or strategy question. When a run reveals that the plan is wrong, the boundary is wrong, or the approach must change, the Operator does not edit the Issue or improvise a new plan. It routes the question back to the Planner (severity: strategy for approach, severity: execution for a missing detail), and waits for a re-plan or a redispatch.
The hand-off is malformed when — the Operator is handed a task that is not dispatchable (no Issue, an unmerged dependency, an open conflicting sibling) and asked to run it anyway, or when the Operator edits the plan, the Issue, or the criteria instead of routing the change back. Either way the run seat has taken on planning authority it does not hold.
What it does not carry — the power to move a task between tranches, re-size it, or rewrite its criteria. Those are scoping decisions, and they belong to planning. The Operator surfaces the need; the Planner exercises the authority.
How it physically runs — downward, the carrier is the dispatchable Issue itself, made ready by the Planner's dispatch act and confirmed at the Operator's own entry gate. Upward, the carrier is an escalation whose severity routes it to the Planner. Starting the run is a controller call against an already-ready task, not a status write.