Codex Desktop ignores MCP App height update and leaves ~400px of blank space

Environment

• ChatGPT desktop app: 26.715.61943 (build 5628)
• Bundled Codex engine: 0.145.0-alpha.27
• macOS: 26.5.2
• Shared feedback session: 019f843e-4616-7c12-8d0e-caeae4eeb6f3

Issue

An MCP App task widget renders at 77px, but Codex keeps a container approximately 500px high. This leaves 350–400px of unusable blank space below the widget.

Steps to reproduce

1. Display an Octopad MCP App task result in Codex Desktop.
2. Let the app render a single task card.
3. Observe the large blank area before the next conversation content.

Expected behavior

Codex should resize the widget container to the content height requested by the MCP App.

Investigation evidence

• The Octopad widget build passes.
• The rendered card measures 77px.
• The app sends ui/notifications/size-changed with { width: 760, height: 77 }.
• A host simulator reproduces the blank space when it ignores this message and keeps a 500px frame.
• When the simulator applies the requested 77px height, the blank space disappears.
• The same widget code and data were used in both cases.

This places the failure after the MCP App sends the correct size: Codex either ignores the update or later overwrites the frame height.

The screenshot and full investigation are included in the shared feedback session.