Sidebar: group threads by project in collapsible boxes, with the latest agent reply on each row

[NickMarcha]

Area: apps/web (Sidebar)

Problem or use case

I run T3 Code across 4 machines and keep one long-lived thread per project per machine. When I switch threads, I want to know three things at a glance: which project, which machine, and what the agent last said.

The sidebar answers the first one, but it repeats the project on every card. For the machine, the environment icon is too small for me to rely on, so I've ended up renaming every thread after its machine. For the last one, nothing in the row tells me what the agent last said, so I open threads just to check where they are.

Proposed solution (images attached)

Preferred: collapsible project boxes. Each project gets a soft container with a thin collapsible header showing the project icon, name and thread count. Its threads sit inside as compact rows, each with the title, status or time, and the start of the agent's latest completed message. The branch only shows when it isn't the default. Collapsing a project hides its threads and leaves a one-line summary.

Lighter alternative: project name on a divider. The list stays flat, but a thin divider with the project's icon and name sits above each run of threads from the same project. Cards drop their own project name, the branch moves to the top line next to the time or status, and the bottom line shows the latest completed reply. Cards stay the same height as today, and it works with any sort order, including manual.

Minimal version: today's cards with the latest reply on the bottom line, the branch moved to the top line, and a plain divider between projects.

In all three, snooze, settle, pinning and the Snoozed/Settled sections work as they do now. Using the latest completed message means the preview doesn't flicker while the agent is still writing.

Images

Today

Project boxes (preferred)

Project name on divider

Minimal version

Related

• feat(web): group sidebar threads by project #13815 grouped sidebar threads by project and was closed pending an agreed direction, which is why I'm raising this here first.
• Sidebar: group the inbox by environment, project or provider — with rows that stop repeating themselves #7836 proposes grouping the sidebar by environment, project or provider.
• fix(web): sidebar rows show the branch again, not a truncated plan step #5776 restored the branch to the bottom line after it showed truncated plan steps. The alternatives above keep the branch visible by moving it to the top line.

A personal note

Since #5672 the default sidebar is a flat list, with the older project-grouped sidebar kept as a legacy option. I don't know whether grouping is something you'd want back in the default, or whether a sidebar redesign is already planned. The project boxes are what would work best for me, and the divider version would be my second choice. Posting here first, as CONTRIBUTING asks.