#399

frontend/AGENTS.md

@@ -130,6 +130,13 @@ pass or the remaining failure is clearly blocked.
 
 - Tailwind scans `src/**/*.{html,js,ts,jsx,tsx,mdx}`.
 - Use `cn` from `src/lib/utils.ts` for conditional class names and class merging.
+- In JavaScript, JSX, TypeScript, and TSX, use `cn` from `@/lib/utils`
+  whenever `className` combines multiple values, conditional classes, or a
+  caller-provided `className` prop.
+- Do not construct `className` with template literals, `${ ... }`, string
+  concatenation, arrays joined with spaces, or feature-local class-merging
+  helpers.
+- A static `className="..."` containing only fixed classes does not need `cn`.
 - Reuse components from `src/components/common`, `src/components/layout`, and
   `src/components/ui` before adding new primitives.
 - Keep Tailwind classes consistent with nearby components.
@@ -140,6 +147,12 @@ pass or the remaining failure is clearly blocked.
   short Japanese labels that fit the control.
 - Preserve existing Japanese tone and orthography in nearby UI text, including
   old-kana wording where the file already uses it.
+- Do not add user-facing copy, helper text, descriptions, notes, tooltips,
+  placeholders, empty-state messages, loading messages, or explanatory text
+  unless the user explicitly specified the wording.
+- When new user-facing wording appears necessary, ask the user for the exact
+  wording and placement before implementing it.
+- Do not invent replacement copy when removing unrequested wording.
 - When adding dynamic tag colour classes, update `tailwind.config.js` safelist
   if the class cannot be statically detected.
 - Do not introduce new UI libraries or production dependencies without approval.