Sheet order is frequency, then weight: grouping is the everyday verb and sits on top; Archive is last, under a hairline-separated SESSION label, with a one-line consequence caption — hides on all devices. It is not destructive-red: archiving is reversible, and red is reserved for deny / delete.

Degradation rule: when a project has no groups, the MOVE TO GROUP section and its label disappear — a section header over an empty list is worse than no header. The SESSION label goes too (a label needs a sibling to distinguish from), so the sheet is a flat two-row list. The session title is doing the heading work in both states, so nothing moves when groups appear later — the sheet only grows upward. The empty-group prompt is a dashed hint at the bottom, not a row: it is a way in, not a verb on this session.

Verdict on the take-back gesture: a persistent trailing icon, 44dp, one tap, no confirm. Swipe was rejected — this screen is entered rarely, so a gesture nobody rehearses is a gesture nobody finds; long-press was rejected because it hides the only verb this screen exists for behind the same gesture that got you here. A row that stays running keeps its green dot: archived ≠ stopped. Tap anywhere else opens the session and it stays archived.

Verdict on feedback: a toast, but never an “Undo”. There is no undo stack, and there does not need to be — archive and unarchive are exact inverses, so the toast simply offers the opposite verb (here Archive; after archiving from the chat it reads Unarchive). It is honest about what happened, it names where the session went, and it costs engineering nothing. Same toast fires on the archive side, where it matters more: a row vanishing from a list you were reading needs a receipt. Toast is 4s, tap-to-dismiss, never blocks the composer.

The empty state teaches the gesture that fills it, and pre-empts the two questions the model raises: does it stop? (no) and is it just this phone? (no). No illustration, no button — there is nothing to act on here.

Menu order = edit the session → file the session → hide the session, with a hairline before the last pair, and the two hiding verbs deliberately adjacent so the difference is read, not guessed. Archive session carries a box glyph and the shortcut; Remove from recents carries the same ✕ as the hover control, so the row control and the menu item are visibly one feature. Neither is red: nothing here loses work.

The row hover ✕ keeps its meaning by keeping its size — a 22px glyph that lives on the row, appears on hover, and undoes itself the moment you open the session again. Archive is never on the row: persistent, cross-device state is not a hover-weight action. And the footer entry carries a count, not a keycap — it reads as a place with contents, and it is the only sidebar row that grows when you archive something, which is the desktop's ambient receipt.

Ruling on the conflict: keep the ⌘K scope, do not build a second panel. A separate browser is a whole surface, a search field and an empty state for a list you visit monthly — and it would fork “find a session” into two places, which is exactly what archive is meant to un-fork. The palette already is the desktop's find-anything room; ARCHIVED is a scope inside it, entered by the sidebar row or by ⌘K → arch.

What actually fixes discoverability is not the hover icon — it is the footer legend, which is always visible and names both verbs the moment the scope opens. So: the icon shows on hover and permanently on the selected row (keyboard users never touch a mouse and must still see it), the label Unarchive is spelled out on the selected row only — icon alone on hover — and the footer carries ⏎ / ⌘⏎ / ⎋ at all times. Scope is a terracotta tag in the query field, so you always know which list you are typing into; ⎋ leaves the scope before it closes the panel.