Codex TUI stalled after successful file creation

Issue Summary
A Codex session stalled in the OpenSpec artifact workflow right after creating the design artifact for change react-core-phase-4-stability-convergence. The UI stayed on “Planning design artifact” for several
minutes and did not emit the next user-facing message, even though the artifact write had already succeeded.

Environment

• Tool: Codex TUI (GPT-5.3 Codex medium)
• Date observed: March 4, 2026
• Workflow: OpenSpec change creation + proposal/specs/design progression

What Happened

1. The session created the change and progressed through proposal/spec steps normally.
2. It entered design planning.
3. The design artifact was successfully added (design.md creation completed).
4. Immediately after, the session executed a status check command for the same change.
5. No further user-visible progress was shown; the UI appeared stuck for an extended period.

Key Evidence (sanitized)

• Session/thread id: 019cb98b-56d1-72a3-8aa4-5f44a29620b0
• Sequence observed in logs:
• apply_patch started for design artifact
• Add File .../react-core-phase-4-stability-convergence/design.md
• End Patch
• openspec status --change "react-core-phase-4-stability-convergence"
• This confirms artifact creation succeeded before the perceived stall.

Expected Behavior
After successful design artifact creation, Codex should promptly continue with the next workflow step and emit a user-facing update (status summary / next action).

Actual Behavior
The session remained in a “planning” state with no follow-up output, giving the impression of a hang despite successful backend actions.

Impact

• User uncertainty about whether work completed
• Duplicate/redundant retries likely
• Reduced trust in long-running OpenSpec flows

Probable Cause (hypothesis)
Not a file-write failure. More likely a post-tool-call progress/reporting gap or session-loop/model-response stall after command completion.