Desktop agent is not resumed when a background exec session completes

Product

Codex desktop agent invoking Codex CLI through a long-running exec/PTY session.

Problem

When an exec command yields a session ID and continues in the background, completion is not delivered back to the parent agent as an event. The parent can discover completion only by explicitly polling the session. If the conversational turn has already ended, the workflow cannot automatically resume and run its next step.

Reproduction

1. From a Codex desktop task, start a long-running command such as codex exec.
2. Let the command yield a PTY/session ID while it keeps running.
3. End or yield the parent turn.
4. Allow the child process to finish.

Actual behavior

No completion event wakes or resumes the parent task. The result remains undiscovered until the user sends another message or the agent manually polls the PTY session.

Expected behavior

The parent task should receive a terminal-session completion event containing at least the session ID, exit status, and an output cursor. It should then be able to continue the workflow, similar to completion notifications from managed subagents.

Impact

Long-running CLI orchestration requires busy polling or user reminders. Multi-stage flows such as generate, review, and package cannot reliably proceed unattended.

Environment

• Codex CLI 0.153.4
• macOS
• Codex desktop task using an exec/PTY tool

A completion callback from the app-server or desktop terminal-session layer would address this without requiring output polling.

Start at the app-server or desktop terminal-session layer responsible for exec/PTY sessions, then reproduce the long-running Codex CLI command described in the issue. Done means the parent task receives a completion event with the session ID, exit status, and output cursor, allowing it to resume without polling or another user message.