Codex App: add message bookmarks to the existing conversation minimap

What variant of Codex are you using?

App (Windows; applicable to the desktop app generally)

What feature would you like to see?

Problem

Long Codex App threads are difficult to navigate when I want to return to a few specific messages. Find in chat helps only when I remember the exact wording, while manual scrolling through a long thread is slow.

A common example is using GPT for learning. I may start from one useful answer, continue with a long chain of follow-up questions to understand the topic more deeply, and then want to return to the original explanation. By that point, the source message may be far above in the thread, so getting back to it requires a long and imprecise scroll.

The app already has a compact conversation minimap / scroll-position rail that can show a message preview on hover. However, there is no way to mark a specific message as a persistent return point.

Proposed interaction

Add manual, thread-local bookmarks directly to the existing conversation minimap:

1. Right-click any user or assistant message and choose Bookmark.
2. Show a visually distinct bookmark marker at that message's position in the existing minimap.
3. Hovering the marker shows the same style of message preview already used by the minimap.
4. Clicking the marker scrolls to the exact source message and briefly highlights it.
5. Right-click the message again, or use an action in the preview, to choose Remove bookmark.
6. Keep bookmarks after the app restarts.

Reusing the existing minimap keeps the feature compact and makes bookmarks feel like persistent conversation anchors rather than a separate knowledge-management system.

Suggested MVP scope

• Manual bookmarks only.
• Whole user or assistant messages only.
• Bookmarks are local to a thread.
• No tags, folders, notes, AI-selected bookmarks, or cross-device sync.
• Bookmarked markers should remain distinguishable from ordinary minimap markers and expose an accessible label.

Acceptance criteria

• A message can be bookmarked and unbookmarked from its context menu.
• Every bookmarked message has a persistent marker in the conversation minimap.
• Hovering a bookmark marker previews the source message.
• Clicking a bookmark marker returns to the exact message.
• Bookmarks survive closing and reopening the app and thread.

Additional information

Related issues: #23350, #22627, and #32066.

This proposal specifically refines #23350 by reusing the existing conversation minimap instead of introducing a separate bookmarks panel. If maintainers prefer to track this as part of #23350, this issue can be linked or consolidated there.

Image 1: Current conversation minimap and the intended bookmark-marker location, indicated by the red annotation.

Image 2: Example of the existing hover-preview interaction. The conversation text shown in the preview is not part of this request; only the interaction and placement are relevant.

Start by locating the existing conversation minimap, its message hover preview, and the message context-menu entry point in the desktop app. Trace how thread state is persisted and verify that bookmarks can identify exact user or assistant messages across restarts. Done means the listed bookmark, minimap, navigation, preview, accessibility, and persistence acceptance criteria all work.