A sentence cue is a cue with scope: sentence: instead of one word, the whole sentence highlights, and cycling swaps in alternative rewrites of it. The shipped more-formal cue turns thanks a bunch. into Thank you very much. with one keypress.
Cues, not agents
Your buffer keeps the original sentence until you explicitly cycle: sentence cues never rewrite anything in the background. Inside their span they outrank word cues (so the two don't fight over the same words), and they always defer to an explicit _.
Adding your own register
A sentence cue is one CUE.md with scope: sentence and a prompt: more casual, plain-language, active-voice, more concise. No word triggers needed, no code, hot-reloaded like everything else.
On by default, and scoped where it makes sense
Sentence cues are on out of the box (they're passive, so nothing changes without a keystroke); set sentence-cues-mode: off to silence them. The shipped more-formal cue only runs where formal register is wanted: professional writing surfaces like LinkedIn and web email (Gmail, Outlook, Proton, Yahoo). It stays out of casual places (forums, Reddit) and the coding CLIs, where a background formality rewrite would just be noise. One honest caveat: the sentence splitter is deliberately simple (a regex over terminators, including CJK punctuation), so exotic abbreviations can occasionally split oddly; the model just declines those and nothing changes in your text.
Related: What is a cue? · Write your own cue · Inline AI for writers · The more-formal cue · GitHub repo