[FEATURE]: Stop a running background subagent from the web app

Feature hasn't been suggested before.

I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

There is no way to stop a background subagent from the web app (packages/app, also used by desktop). If one goes off track or loops, nothing in the UI can stop it.

What I found:

The "background tasks running" popover lists the subagents, but each row only links to the child session.
The child session page replaces the composer with "Subagent sessions cannot be prompted", so it has no Stop button either.
Stop on the parent only interrupts the parent. A Sep 24 comment on Interrupting the main agent does not stop background subagents #28738 reports subagents are not stopped when the main session is interrupted (Desktop 2.0.16).

The server already supports this. POST /api/session/{childSessionID}/interrupt stops just that subagent, and the TUI uses it (ctrl+d in the Subagents tab). The web app never calls it for a child session.

Suggestion: a stop button on the subagent rows in the popover, and one in the child session view. This would bring the web app in line with the TUI. #46343 covers the child view, but it has merge conflicts with v2 and has had no review.

Related: #36423 (cancellation for background subagents, framed around a model tool), #46343, #46721 (stop outcomes for background work).

This issue might overlap with existing requests. Please check:

#38966: Requests individual steer, cancel, and abort controls for running subagents, including human controls.
#36423: Requests cancelling a running background subagent by session ID.

For keybind-related issues, please also check our pinned keybinds documentation: #4997

Thanks for the detailed write-up! You're asking for a way to stop a single running background subagent from the web/desktop app: from the subagent rows in the "background tasks running" popover, and from the child session view.

Part of this has landed since you opened the issue. Starting with v2.2.0, subagent rows in the background activity popover can be stopped. Hover a row and the run time turns into a stop button, or focus the row and press Delete/Backspace. This interrupts only that subagent's session. It works once the subagent's child session has been created. The child session view itself still has no stop control, so that part of the request is still open.

Maintainers will consider the rest. Related issues and PRs:

[FEATURE]: A running subagent cannot be steered, cancelled, or aborted individually #38966: individual steer/cancel/abort for running subagents (broader, mostly TUI and agent tools)
v2: subagent: no cancellation support for background subagents #36423: cancelling background subagents from a model tool
[FEATURE]: agents: expose child-session observability and recovery tools (status/messages/context, fork+prompt, cancel) #59566: agent-facing tools to inspect, recover and cancel child sessions
feat(app): stop viewed subagent with keybind #46343: earlier PR adding a stop control to the child session view (closed)
Interrupting the main agent does not stop background subagents #28738: interrupting the parent didn't stop background subagents
feat(app): add subagents side-panel tab #55496: open PR adding a Subagents side-panel tab

Navigation Menu

Repository navigation

[FEATURE]: Stop a running background subagent from the web app #52016

Feature hasn't been suggested before.

Describe the enhancement you want to request

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

[FEATURE]: Stop a running background subagent from the web app #52016

Description

Feature hasn't been suggested before.

Describe the enhancement you want to request

Activity

github-actions commented on Sep 29, 2026

opencodejr commented on Oct 28, 2026

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions