Subagent Activity

When a Claude Code agent spawns subagents via the Agent tool, Workbench surfaces their progress in three places: a sidebar activity indicator with expandable detail, a resizable Subagents panel, and per-session tab badges.

Sidebar Indicator

The workspace sidebar normally shows a ring spinner when an agent is running. When one or more subagents are active, the spinner changes to an orbiting-dots animation — three small dots circling a center point. This appears when:

• The agent status is IdleWithBackground (main agent finished but subagents are still running), or
• The agent status is Running and at least one subagent is active

The orbiting dots replace the standard spinner to signal that background work is happening, even if the main agent’s turn appears complete. Higher-priority indicators (agent questions, plan approvals) still take precedence.

Expandable sidebar detail

Each workspace row in the sidebar shows an expandable section listing running subagent descriptions and their current tool. This gives a cross-workspace view of subagent activity without switching context — you can see what every workspace’s subagents are doing at a glance.

Subagents Panel

The Subagents panel is a resizable bottom panel (like the terminal panel) that shows all subagents for the active session. Because it sits below the chat, you can watch subagent progress and chat simultaneously.

What each row shows

• Status dot — green for running, gray for completed, red for failed
• Task label — the Agent tool’s description input, shown as a bold prefix. This tells you why a subagent was spawned, not just what it’s currently doing.
• Activity text — real-time description of what the subagent is working on
• Last tool — the most recent tool the subagent used (e.g. “Bash”, “Edit”)
• Tool count — how many tool calls the subagent has made
• Elapsed time — live-updating timer for running subagents, final duration for completed ones

Visual states

• Running — normal text with a green status dot and live timer
• Completed — struck-through dimmed text, signaling the work is done
• Failed — red “Failed:” prefix followed by struck-through description text

Ordering

Running subagents appear first, sorted by start time (oldest at top). Completed and failed subagents follow, sorted by completion time (most recent at top).

Auto-show and auto-hide

The panel opens automatically when the first subagent starts in the active session. It auto-hides 3 seconds after all subagents in the session complete. Failed or unknown-state subagents keep the panel open until manually closed.

Closing the panel manually hides it. If a new subagent starts later, the panel reappears automatically.

Per-session scoping

Panel visibility is scoped per workspace — opening or closing the panel in one workspace does not affect others. Navigating to a workspace with running subagents auto-opens the panel.

Session tab badges

When a workspace has multiple concurrent chat sessions, each session tab shows a running-subagent count badge. This helps you identify which session has active background work without opening the panel.

Workspace panel header

The Subagents panel includes a WorkspacePanelHeader showing the repo/branch breadcrumb, consistent with other session tab types.

Ephemeral data

Subagent activity data lives in the frontend session state only. It is not persisted to the database. During active work, subagents emit frequent progress events so the view stays populated. After a page refresh, completed subagents from earlier turns are not reconstructed.