active-snippet-mode
active-snippet-mode: live only while a snippet is expanding — Tab and S-Tab walk its placeholders, Esc leaves the session.
Active only while a snippet is expanding. It owns the placeholder navigation, and it goes away when the session ends.
Chords
| Chord | Action |
|---|---|
<Tab> | Next placeholder |
<S-Tab> | Previous placeholder |
<Esc> | Leave the snippet session, then exit Insert |
Why the scoping matters
<Tab> is not a key you can casually rebind — in Insert it inserts a tab or triggers completion, depending on context. Binding "next placeholder" to it globally would be wrong; binding it only for the duration of an expansion is exactly right.
That is what this mode buys: the chords exist while a snippet is in flight and not one keystroke longer. Finish or abandon the expansion and <Tab> goes back to meaning what it always meant.
<Esc> falls through
<Esc> here does two things in order: ends the snippet session, then continues to the native <Esc> (exit Insert). It doesn't shadow the key — it augments it, so muscle memory keeps working and you don't need two presses.
See also
snippet-mode— the gate, and<C-x><C-s>to start an expansion.snippet-completion-mode— snippets as completion candidates.