Distinguish "explain or assess this" from "change this" before touching any file. Use whenever a message could be read either as a question or as a change request — bug descriptions ("the export breaks on empty rows"), "why does X happen", "is this a bug", "what do you think of Y", "should we / could we", thinking-out-loud messages, and pasted errors with no instruction. Not for bare imperatives ("fix", "add", "refactor"), which are tasks.
