[DOCS] Background subagent docs omit elapsed duration shown in completion notifications

Documentation Type

Missing documentation (feature not documented)

Documentation Location

https://code.claude.com/docs/en/sub-agents

Section/Topic

"Run subagents in foreground or background" and related background-task result/notification guidance

Current Documentation

The docs currently explain that background subagents run concurrently and that their results return to the main conversation, but they do not document the new elapsed-duration text now shown in completion notifications:

Background subagents run concurrently while you continue working. They run with the permissions already granted in the session and auto-deny any tool call that would otherwise prompt. If a background subagent needs to ask clarifying questions, that tool call fails but the subagent continues.

When subagents complete, their results return to your main conversation. Running many subagents that each return detailed results can consume significant context.

Related task-surface docs likewise stop at generic task management and output access:

/agents opens the manager for the subagents Claude can delegate side tasks to, and /tasks lists what's running in the background of the current session.

The tasks pane shows the background work running inside the current session: subagents, background shell commands, and workflows. Click any entry to see its output in the subagent pane or stop it.

What's Wrong or Missing?

Claude Code v2.1.144 added elapsed duration to background subagent completion notifications, for example Agent completed · 3h 2m 5s.

The current docs describe background subagents, /tasks, and the desktop tasks pane, but none of those pages mention that completion notifications now include runtime duration. That leaves the documentation incomplete for users who rely on notifications or task surfaces to understand how long a background subagent ran before opening the transcript or task output.

Suggested Improvement

Add a short v2.1.144 note wherever background subagent/task completion behavior is documented, preferably on the subagents page with cross-references from task-oriented pages.

For example:

When a background subagent finishes, Claude shows a completion notification that includes the elapsed run time, such as Agent completed · 3h 2m 5s. This helps you assess how long the subagent ran before opening its transcript or task output.

If the same duration also appears in /tasks or desktop task panes, name those surfaces explicitly so the docs match the UI.

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Line(s) | Context |
|------|---------|---------|
| https://code.claude.com/docs/en/sub-agents | 681-720 | Background subagent behavior and result-return guidance |
| https://code.claude.com/docs/en/commands | 23 | /tasks is introduced as the way to inspect background work in the current session |
| https://code.claude.com/docs/en/desktop | 307-311 | Desktop tasks pane for subagents/background work |

Total scope: 3 pages affected

This gap appears to be specific to the Claude Code v2.1.144 release entry: added elapsed duration to background subagent completion notifications.