Design systemDraft

Message actions

Under every message one icon row (hidden until the message is hovered, keyboard-focused or long-pressed; its room is kept so nothing jumps): Copy (Shift-click copies as Markdown), Reply, Ask about this, and ..., a menu with Copy as Markdown, Copy code, Edit and Retry (your own), Branch from here, React and Pin. Each icon has a tooltip with its name and key.

Keyboard: Alt+Up in the message box selects the last message; Up and Down move; R reply, C copy, Shift+C copy as Markdown, A ask about it, E edit your own, B branch, P pin, M open the menu; Esc returns to the box. The key decisions are pure (apps/app/src/chat/message-keys.js).