When I'm stressed I fire off messages that are technically fine but read as cold or passive-aggressive, and then I spend the afternoon doing damage control.
Build a prompt that takes my {{draft}} message and a {{context}} note (who it's to, what outcome I want) and returns 2-3 rewrites along a tone dial: 'softer', 'neutral-clear', and 'warm-direct'. It must preserve my actual point and any hard requirements or deadlines, remove accidental sharpness, and never become so padded that the ask gets lost. Keep each version roughly the original's length.
A strong solution adds a one-line note on what it changed and why for each version, and flags when my original is actually fine as-is so I don't over-soften a perfectly reasonable message. Show it working on a draft that's borderline rude but contains a genuinely firm deadline that must survive the rewrite.