#31424 Subagent tray: no 3/4 ring, no View all (the list scrolls), a settled tray keeps its own surface

Leo, 2026-11-01, on the settled Subagents tray (a ring before "Subagents", three chat lines, then "View all 4"):

why did you guys not remove the 3/4 and why did you still not fix the stupid gap and you f***ing glassed way too hard now there's no difference at all but ok but why is there even a view all 5 button it's useless just let it be scroll-downable

i mean you can't just have it be the exact same glass as the background

Spec: leo-workspace design/running-tray.md (surface running-tray).

What changes (webviews/src/agent-session/acpmux/subagents):

• No 3/4 ring. The header's mark (app.sample.runningagents, which reads as a 3/4 circle) is off by default: trayHead.experiment.ts now defaults to bare. The icon slot stays, blank (visibility: hidden), so "Subagents" and the counts keep the lines' text column (--grid-tray-text) and don't jump to the inset.
• No View all. Every line that ended is in the list, which already scrolls past five lines (eight in the tall arm). The View all N / Show fewer button, its divider, TRAY_OPEN_MAX and the dock's second reserved row (bottomStack.css) are gone.
• A surface of its own, and no gap. #29276 removed the card from a settled tray, so the header and lines sat on the chat's own glass. A headed settled tray now draws a faint tint (the theme's text at 5%, see-through) with the composer's hairline rim. It joins the composer as one glass, the same way the running tray does ([data-card] replaces :not([data-settled]) in the join rules), so there's no seam or notch between them. A lone ended line, with no header, stays bare as #29276 set it.
• New experiment traySurface.experiment.ts (arms tint (shipped), rim, card, none) and the gallery entry agent-pane.subagent-tray-surface (variants four and twelve). Compare the arms there.

Tests updated: subagent-tray.test.tsx (no View all, a blank header mark, a settled headed tray keeps data-card), subagent-tray-columns.test.ts, running-strip.test.ts, support/gridScenes.ts (footer lines dropped).

Risk: small and contained to the tray. One follow-up: with View all gone, an opened tray renders every ended line instead of three. It is only built while the tray is open (#29250 still skips it when folded).

Agent session: agent session

🤖 Generated with Claude Code

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Summary by cubic

Fixes the subagents tray per Leo's feedback: removes the 3/4 ring and the "View all" button (the list now scrolls through every ended line), and gives a settled headed tray a surface of its own so it no longer reads as the chat's background glass.

• The header's mark is off by default; its slot stays blank so "Subagents" and the counts keep the lines' text column.
• "View all N" / "Show fewer" and its divider are gone, along with TRAY_OPEN_MAX and the dock's second reserved row.
• A headed tray with nothing running draws the theme's text at 5% with the composer's hairline rim, joining the composer as one glass with no gap; a lone ended line stays bare.
• New experiment traySurface.experiment.ts (tint ships; rim, card, and none render for comparison).
• Follow-up: an opened tray now renders every ended line instead of three, and only builds it while open.