A Pane Is Not a Composer
Anvil preparation produces a draft. Firebrand idle-resume produces a draft. Both look, from a distance, like "put this text in the terminal." They are not. A PTY identity is not a conversation identity. The pane is a shell, or a vendor CLI, or a harness that happened to print a prompt. The draft is a document about a seat, a phase, a run. Glue those together with an automatic paste and a synthetic Enter, and you have submitted last seat's prompt into this seat's brain, or submitted a stale phase into a live one. Vendor CLIs do not expose a common empty-composer contract. There is no honest "the composer is empty now" signal to hang an automatic submit on.
So the draft stays in a native preparation view, outside the PTY. You can see it. You can copy it. You can look at the visible conversation in the pane. You paste. You press Enter yourself. The human is the join between two identities the machine cannot prove are the same. That is not ceremony. It is the only join that does not lie.
Copy, Inspect, Paste, Enter — All Yours
The bounded native handoff is allowed to be convenient. A button that copies. A layout that puts the draft next to the pane. A warning when the seat or the phase on the draft does not match the pane's declared identity. Convenience stops before the newline. The app does not press Enter. The app does not paste on a timer. The app does not wait for a prompt-ready heuristic and then fire. Heuristics on vendor CLIs are how you ship a submit into a pager, or into a confirmation, or into a password prompt.
Firebrand's idle resume is the same policy in a different coat. A coding engine that was waiting can be brought back to a pane. The text that should continue the work is still a draft until you put it there. Auto-resume that types is auto-submit that forgot its name. The pane may already have a partial line. The conversation may have moved. The only person who can see both at once, in the moment, is you.
The Door Still Does Not Type
It is tempting to punch a hole: let Anvil call a special input verb, just for drafts, just for seats. That hole is the generic input verb from the first lesson of this track, wearing a friendlier name. The door launches the pane. The preparation view holds the draft. The glass in between is the operator. If a future sibling cannot live with that, the answer is not a hole. The answer is a better preparation view — still outside the PTY — or a refusal to support a harness that cannot be prepared honestly.
The phone will inherit this exact policy. Track 6 will say Anvil on the phone uses the same preparation: drafts outside the PTY, refuse a stale phase. The phone does not get automatic Enter because the keyboard is smaller. If the Mac already synthesizes Enter, the pocket will too, and four Anvil seats on a train become four silent submits. Hold the line here, on the desktop, where you can see all four panes at once.