Subagent Missing

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

When an agent spawns a subagent, opening the subagent in a new tab before it starts causes the tab to remain stuck in an empty state. Additionally, the subagent preview in the parent agent is incorrectly marked as completed, while the subagent continues running in the background.

Steps to Reproduce

  • Prompt a parent agent to spawn a subagent (for example: “spawn a subagent for testing”).
  • As soon as the subagent preview appears, quickly click it to open the subagent in a new tab.
  • Subagent tab remains in an empty state, while the subagent preview in the parent agent is immediately marked as completed.

Screenshots / Screen Recordings

SCR-20260618-ngck.png
SCR-20260618-ngck.png1702×994 49.5 KB

Operating System

MacOS

Version Information

Version: 3.7.27
VS Code Extension API: 1.105.1
Commit: e48ee6102a199492b0c9964699bf011886708ba0
Date: 2026-06-10T01:46:16.942Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
xterm.js: 6.1.0-beta.256
OS: Darwin arm64 25.5.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the detailed report with the video and steps, that really helps.

There are two separate behaviors here:

  1. Empty tab if you click during Starting up: if you click the subagent card while it’s still in the warm-up phase, it opens an empty tab that never picks up the running subagent. Workaround: wait until the subagent shows active progress, then open it. Clicking specifically during Starting up is what causes the empty tab. We fixed something similar before, and it looks like it came back in 3.7.27, I’ve reported it internally as a regression.

  2. The subagent preview shows Completed even though it’s still running: this is a known display bug and it’s already being tracked. The subagent itself keeps running correctly in the background.

I can’t share an exact ETA for a fix yet. If anything changes after updates or you notice something new, please post here.

8

Awesome, thanks for picking this up!