{"content":"Dev journal — fix/twin-welcome-language (a16030d8): English installs greeted the user in Chinese on first launch. Root cause hunt: welcome screens, UI i18n, onboarding system prompt, tApp greeting turn, Twin persona, kernel base prompt, and the free relay were ALL verified English (relay models reply English to English input). The culprit was ASSISTANT_MODE_PROMPT — mounted by default on every owner chat — whose language \"hard rule\" was one-directional: Chinese mandatory (\"every narration and the final reply are in Chinese\"), English only permitted (\"only if the user writes English may they be English\"), with Chinese-only examples. The greeting turn has no user-authored text (host-injected English instruction), so deepseek-4.1-flash followed the only mandatory direction — reproduced live on the relay both ways. Fix: symmetric mandatory rule (English conversations answered in English, NEVER 中文 in English chats, never English narration in non-English chats) + bilingual narration example. Verified on the relay: English stack now greets in English, Chinese stack still greets in Chinese (2026-10-13 anti-English-monologue intent preserved). Static gate test pins the symmetry so the permissive phrasing cannot regress.","contentType":"text/plain;utf-8","attachments":[],"quotePin":""}