Workers pane shows duplicated worker entry after Ctrl+Z (SIGTSTP) + fg

[kang1027]

Pre-submit Checks

• I have searched Warp bugs and there are no duplicates
• I have searched Warp known issues page and my issue is not there
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Describe the bug

The Workers pane in Warp displays the active worker as a duplicated entry after the foreground process is suspended with Ctrl+Z (SIGTSTP) and resumed with fg. The original worker card remains, and another instance of the same worker appears as a separate entry.

Not specific to a single CLI — reproduces with both Claude Code (claude) and OpenAI Codex CLI (codex), so it looks like a Warp worker-state tracking issue around job control rather than a TUI program issue.

To reproduce

1. Open a Warp window with a Worker running a long-lived TUI program
   • (e.g. claude or codex) inside a project directory
2. With that worker focused, press Ctrl+Z to suspend the foreground process (SIGTSTP)
3. Run fg %1 to bring the process back to the foreground
4. Look at the Workers pane (sidebar)

Expected behavior

The same worker entry remains displayed once, with no duplicate. State should be unchanged from before the suspend.

Screenshots, videos, and logs

Operating system (OS)

macOS

Operating system and version

macOS 26 (Darwin 25.3.0)

Shell Version

zsh 5.9 (arm64-apple-darwin25.0)

Current Warp version

v0.2026.04.29.08.57.stable_01

Regression

No, this bug or issue has existed throughout my experience using Warp

Recent working Warp date

No response

Additional context

Reproduces consistently with multiple TUI CLIs (Claude Code, Codex CLI), which suggests Warp's worker tracking is double-registering the same PTY/job after fg, rather than this being a quirk of a specific program's redraw behavior.

Does this block you from using Warp daily?

No

Is this an issue only in Warp?

Yes, I confirmed that this only happens in Warp, not other terminals.

Warp Internal (ignore): linear-label:b9d78064-c89e-4973-b153-5178a31ee54e

None

[oz-for-oss]

@kang1027

Here's what I found while triaging this issue:

Thanks for the detailed repro. This looks like a Warp worker/session tracking issue around suspending and resuming long-running CLI agents, not a Claude Code or Codex-specific redraw issue.

Maintainer details

I concluded that workers pane can show a duplicate active CLI-agent worker after a long-running foreground TUI is suspended with Ctrl+Z and resumed with fg..

Triage summary

This appears to be a Warp bug in active CLI-agent/worker tracking around shell job control rather than a Claude Code or Codex-specific rendering issue. The same worker should remain represented once when the foreground job is suspended and resumed.

Reproducibility

High. The report includes a minimal sequence (Ctrl+Z, then fg %1), screenshots of the duplicated worker entry, macOS/zsh/Warp version details, and notes that both claude and codex reproduce the symptom.

Likely affected area

The likely path is the CLI-agent session and conversation/worker list plumbing. CLIAgentSessionsModel tracks CLI-agent sessions per terminal view, TerminalView creates/removes those sessions from long-running block lifecycle events, and the conversation/worker list renders normalized task/conversation entries with separate shadowing logic. A stopped job can return the shell to a prompt without the CLI process actually exiting, then fg resumes the same process under a new foreground command; that transition likely causes the same logical worker to be registered/rendered twice.

Duplicate check

I did not find two open issues matching this specific duplicated Workers-pane entry after Ctrl+Z/fg. Existing Ctrl+Z-related issues such as #3240 and #1941 cover different job-control/keybinding behavior rather than duplicate worker rows.

This is my automated analysis and may be incorrect. A maintainer will verify the details.

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