[Feature]: Render Codex inline artifact and edited-files cards in the chat timeline

[kevin-stuart]

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/web

Problem or use case

When using T3 Code with the Codex backend, assistant turns do not render the inline Codex turn cards that appear in Codex Desktop.

In Codex Desktop, the assistant transcript can include inline cards at the exact point where the assistant references files or edits, for example:

• a file/artifact card such as strawberry-apple-silicon-report.md with Open in
• an Edited 2 files card with per-file diff stats
• turn-local Undo and Review actions

In T3 Code, the same area in the chat timeline is blank. The right-sidebar diff panel exists, but that is a different surface. The missing piece is the inline, turn-local rendering inside the transcript.

Proposed solution

Render Codex backend artifact/edit summary events as inline cards in the chat timeline, similar to Codex Desktop.

The first version could support:

• inline file/artifact card rows for files produced or referenced by the assistant turn
• inline edited-files summary card with per-file diff stats
• a Review action that opens the existing T3 Code diff panel focused on that turn/file, if possible

Why this matters

The inline placement gives important context. It shows exactly what file or edit the assistant is referring to at that point in the answer.

Without it, the conversation has a visual gap and the review action is separated from the relevant assistant text. The right-sidebar diff panel helps inspect the final state, but it does not replace the turn-local inline context.

Smallest useful scope

A first pass only needs to render the inline edited-files/artifact summary for Codex backend turns in the chat timeline.

It does not need to redesign the diff panel or add new diff functionality. Clicking Review can reuse the existing diff panel.

Alternatives considered

The current workaround is to use the right-sidebar diff panel or a later changed-file pill, but those do not appear inline where the assistant refers to the files.

Risks or tradeoffs

This may need mapping between Codex backend turn events and T3 Code timeline components. It should avoid duplicating the full right-panel diff UI inside the chat; the inline card can stay summary-level and delegate detailed review to the existing diff panel.

Examples or references

Attached screenshots compare:

1. Codex Desktop showing inline file/artifact and Edited 2 files cards.
2. T3 Code using Codex backend showing a blank/gap in the same place.

Related but not duplicate:

• Extract changed files card with compact aligned diff stats #3023 added a ChangedFilesCard, but this request is specifically about Codex-style inline turn cards in the transcript.
• Add diff scope switching and provider update settings #3169 is about diff scope switching in the right-panel diff UI.
• [Feature]: Add Changed files context menu actions #3522 assumes a Changed files section already exists and asks for context menu actions.

Contribution

• I would be open to helping implement this.