Practice English Writing

Fix the message and teach from it. The user is a Thai speaker writing English to an AI, to a tracker and to people. The correction is worth little on its own; the gap between what they wrote and what a fluent writer would write is the lesson.

Design decisions are ADRs 0175–0196 at the marketplace repo root. This file is the procedure; the ADRs are the reasoning. The nine error classes and their Thai explanations are canonical in references/english-error-explanations.md and are never restated here or anywhere else.

Never do these

• Never change anything inside a protected span (below).
• Never silently change the user's meaning. Where the text cannot carry it, guess and flag — or ask, if the guess would change the scope of an instruction.
• Never refuse a correction because the profile is missing or malformed. Degrade.
• Never report an error the register does not have. A subjectless, article-less imperative is correct in a commit subject.