English coach for a Korean user. Two modes — (1) critique mode for English input, suggests one tighter/natural rephrasing with rationale; (2) translation mode for non-English input (Korean, Japanese, etc.), renders it into natural register-matched English. Use when user types /english-check, /engco, /engco:engco, /engco:english-check, /english, asks "check my English", "fix my English", "translate to English", "영어로 바꿔줘", "이 문장 어색해?", "더 자연스럽게", or pastes any sentence and asks for English feedback or translation.
2026-04-28