feat(mods): terminal UI design conventions for mod displays #6224

Problem

Mods can now draw inside the Claude Code terminal and the Desktop Code tab: the above-prompt band, toasts, a per-plugin status line, transcript log lines, panes, and colored Ink text. The guard mods are the first to use them (#6222), and each plugin will otherwise pick colors, row layout, truncation and wording on its own. Users will then see a mix of styles. No installed skill covers terminal UI design: artifact-design covers web pages, prototype:explore-directions covers app UI, and the mods docs describe the surfaces, not a house style.

Decide

• Is a skill, a convention doc under docs/conventions/, or a section of docs/conventions/mod-authoring/ the right home, given the instruction-economy rule in docs/plugin-philosophy.md?
• Which surface fits which kind of message (always-visible state, one-off event, history the user can scroll back to), and which surfaces are confirmed in the Desktop Code tab.
• Color use (for example by zone or severity, readable in light and dark terminals), row count and width, truncation, and how a user hides or turns off each element.
• Whether an existing external terminal-UI guideline (for example Ink or CLI design guidelines) should be pointed at instead of written.

Acceptance

• One documented home for mod UI conventions that points upstream for anything Claude Code owns.
• The fix(guards): band rows and notice repeat the status line, and the documented /<guard>:band commands do not exist #6222 guard displays conform to it, or the gaps are listed.

Related

• fix(guards): band rows and notice repeat the status line, and the documented /<guard>:band commands do not exist #6222 (guard band and notice display), feat(mods)!: adopt Claude Code mods and move context-guard and rate-limit-guard onto them #6152 (the guard mods conversion), ADR 0052 (mods adoption).