---
title: Supermail (part 3)
---
# Supermail (part 3)

## What it is

This is part 3 of the [Supermail](supermail.md) page. It carries the next stretch of the material on that page, moved here because a single page is capped at 40,000 characters.

## Where to find it

Reach this part through [Supermail](supermail.md) — it lists every part and explains where the feature lives in the product. Everything below is reached from the same place.

## How it behaves

Everything below is the behaviour, detail and edge cases that belong to this stretch of the Supermail page.

### Feature status (Superhuman parity)

The authoritative gap analysis + per-feature status lives in
`src/plugins/supermail/SUPERHUMAN_PARITY.md`. As of 2026-06-23 the client is at
near-parity; the non-AI gaps are closed end-to-end:

- **Undo send** is a _true_ deferred send — the composer sends with
  `undoWindowSeconds`, the backend holds it on a `pending_sends` row and fires
  the real `sendMessage` when the window elapses; Undo cancels it server-side
  (`DELETE /messages/pending/:id`).
- **Search** supports negated operators (`-from:`, `-label:`, `-in:`, `-has:`,
  `-is:`) end-to-end (backend `query-parser` → `NOT` clauses; frontend renders
  exclusion chips).
- **Snippets** can carry **attachments** (persisted in `snippets.attachments_json`,
  applied to the draft on insert).
- **Follow-ups** auto-resolve when a reply lands (the incremental sync calls
  `maybeResolveOnNewMessage`).
- **First-run keyboard tour** (`features/onboarding`) drills the core shortcuts;
  replayable from Settings → General → Personalization.
- **Left-handed navigation** (opt-in, OFF by default; Settings → **Keyboard**) — when
  on, **W** = up and **S** = down in the inbox list, alongside the unchanged J/K +
  arrow keys; because bare `s` is normally Star, one-key Star relocates to **D**, and
  **Q** is added as a left-hand alias for **Label** (its `l` still works) while the mode
  is on. Preference persists to `supermail:left-handed-nav`
  (`features/settings/left-handed-nav-setting.ts`). It is applied as an _effective
  keymap_: `getEffectiveKeymap(leftHandedNav)` in `features/shortcuts/keymap.ts` drops
  the bare-`s` Star binding and appends `LEFT_HANDED_NAV_BINDINGS` (w/s/d + q→label);
  both keymap consumers (`app-shortcuts.tsx`, `use-inbox-actions.ts`) read it so `s` is
  never bound to two actions at once. The Shortcuts drawer swaps its nav/Star/Label rows
  via `getShortcutCatalog`; the live help overlay reads the registry and already reflects it.
- **Hover to act** (Settings → **Keyboard**; ON by default) — moving the mouse onto a
  thread row moves the keyboard _cursor_ to it, so the one-key shortcuts (`e` Done, `#`
  Trash, `s` Star, `u` Unread, `h` Snooze, reply/forward, …) act on the hovered
  conversation with no click or explicit select first. It moves the cursor + row highlight
  ONLY — the reading pane still opens on click / Enter, never on hover. Preference persists
  to `supermail:hover-act` (`features/settings/hover-act-setting.ts`); off restores
  hover = prefetch-only. Implemented as `focusRowOnHover` in
  `features/shortcuts/hover-focus.ts`, wired into all three list surfaces (inbox, label
  folders, snoozed) — every shortcut already targets `focusManager.getFocusedId()`, so
  moving focus is all it takes. Each page's focusManager subscriber skips its focus→reading-
  pane mirror for hover-driven focus via `isHoverSuppressingPaneMirror()`, and the existing
  `pointerMovedTo` guard keeps a row that merely scrolled under a stationary pointer from
  hijacking the cursor.
- **Superhuman sidebar** — pinned-vs-overlay nav with a hamburger drawer
  (auto-closes on mouse-leave) and a command-palette account selector. See
  "Sidebar: pinned vs overlay" above.

Still deferred (intentionally): AI (Ask/Summarize/Instant-Reply/Write), team
collaboration, and live calendar — the only ⚙️ items left.

### Sending from an IMAP (non-Gmail) mailbox

- A send goes out through the mailbox's own SMTP server, then a copy is filed in its Sent
  folder with an IMAP `APPEND` (`backend/src/shared/mail/imap/send.ts`).
- The SMTP submission names its recipients explicitly — the sender plus every To, Cc and Bcc
  address — because a pre-built message is never read for recipients. Until 2026-09-26 that
  envelope was missing, and every IMAP send failed with "No recipients defined".
- **Bcc stays private.** SMTP hands the submitted bytes to every recipient unchanged, so that
  copy is built WITHOUT its Bcc line (`buildRfc822` returns both copies); the Sent-folder copy
  keeps it as the sender's own record.
- Gmail mailboxes do not use this path: the Gmail API gets only `raw` + `threadId` and strips
  Bcc itself.

## Related

The overview, the other parts, and everything else worth reading next all sit on [Supermail](supermail.md).