plan.run.Plan.run_over_control_mode

Control mode is the one transport that separates *how many commands* from *how many processes*: every operation is its own protocol block over one connection, so a plan costs one process however long it is and every operation still reports its own outcome. That is the combination a subprocess cannot offer -- there, sharing an invocation is what buys the process back, and it is exactly what costs the attribution.

There is no planner argument because there is nothing to trade: blocks are per command already.

Errors

Returns an error when the connection is closed, a command cannot be written, a slot dependency is invalid, or a creating operation does not return valid IDs. Validation happens before the first command. A command tmux refuses is reported in the [ PlanResult ].