Codex Desktop: allow the Markdown metadata panel to collapse completely

What version of the Codex App are you using (From “About Codex” dialog)?

26.825.6671.0 (Microsoft Store package OpenAI.Codex; bundled app reports 26.825.51511, build 7377)

What subscription do you have?

Not disclosed; this report concerns the local Markdown preview.

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

The rendered Markdown preview displays YAML frontmatter in a Metadata card, but the card cannot be collapsed completely. For documents with several long metadata values, the card can consume most of the reader viewport and push the actual document body below the fold.

The existing “Show more / Show less” control does not solve this. It is only rendered when there are more than eight metadata entries, and “Show less” still leaves the first eight entries visible. A document with exactly eight entries has no disclosure control at all.

No screenshot is attached because the original report contained local paths and project-specific metadata. The synthetic example below reproduces the relevant structure without private data.

What steps can reproduce the bug?

1. Create a Markdown file with exactly eight YAML frontmatter entries:

---
title: Example report
type: research_note
artifact_id: EXAMPLE-001
version: 0.1
status: candidate
decision: pause
authority: C:/example/docs
evidence_cutoff: 2026-08-31
---

# First body heading

This is the document body.

2. Open the file in the Codex Desktop rendered Markdown preview.
3. Observe that all eight metadata rows are always visible.
4. Try the Metadata heading and look for a disclosure control. The heading is not interactive and no control is rendered.

What is the expected behavior?

The Metadata card should be a proper disclosure region that can collapse to a single header row, regardless of how many entries it contains.

Suggested behavior:

• Make the Metadata header a button with a chevron and aria-expanded.
• Support mouse, Enter, and Space activation.
• When collapsed, hide all metadata rows so the document body moves up immediately.
• Keep the header visible so metadata remains discoverable, as requested in #41190.
• Either default to collapsed in local file previews or remember the user's last choice.
• If the existing eight-entry “Show more” behavior is retained, keep whole-panel disclosure state separate from the “show additional fields” state.

Additional information

Inspection of the renderer code shipped in the Windows app bundle shows why this occurs:

• The metadata preview uses a fixed visible-entry limit of 8.
• The overflow condition is effectively entries.length > 8.
• The toggle is rendered only when that condition is true.
• The collapsed overflow state uses entries.slice(0, 8).
• The Metadata title is rendered as a plain div, not a disclosure button.

So the current state models “show extra fields” rather than “collapse the metadata panel.” This is related to, but distinct from, #41190: that issue asks for frontmatter to be discoverable; this report asks for the now-visible metadata region to be fully collapsible so the reader remains usable.

Start at the Markdown metadata preview renderer and inspect the existing eight-entry limit and overflow toggle. Verify the exactly-eight-entry case, then trace the header and disclosure state needed for mouse, Enter, Space, and aria-expanded behavior. Done means the panel can hide all metadata rows while keeping its header visible, without breaking any retained “Show more” behavior.