UX copy rules pitched at the writing that’s easiest to get wrong under deadline: verb-first buttons (“Delete project,” never bare “OK”), one capitalization policy applied consistently, settings labeled for their ON state, and — the rule most worth stealing — never concatenate strings around a variable ("You have " + n + " messages"), because word order isn’t stable across languages.
Its error-copy rule is the sharpest thing in it: an error is an instruction, sited next to the field that broke, with no “Oops” and no blame. The before/after table format (used across this author’s whole skill set) makes every rule falsifiable against real code rather than aspirational.
Install: bundled in jakubkrehel/skills’s .claude-plugin marketplace, or copy skills/better-writing/ directly.
Gotcha: principle #1 is “recon the existing voice” before changing anything — it’s designed to defer to a product’s established terminology, not overwrite it with generic plain-language defaults. Skipping that recon step is the most common way to misuse it.