Review individual tool edits without requiring Git checkpoints

[hyein-cbio]

The need

For small scripts and one-off files, I want to inspect what an edit tool changed without creating a Git repository just for review. A provider may already return the exact patch—for example, Pi's direct edit tool does—but T3's review surface currently shows checkpoint-based turn diffs instead.

I understand from the guidance on #21202 that this is intentional and consistent across providers. This is an enhancement proposal, not a report that the existing Git turn-diff model is broken.

Proposed behavior

When a provider already supplies an edit patch:

• Let the user open that individual tool call's patch from its file-change entry in the existing Diff tab. Label it separately from a Git turn diff.
• Keep the patch body out of chat, and show the action only after displayable output is available—not while loading, after a failed request, or for an empty result.
• Preserve existing Git turn-review and rollback semantics. Two edits to the same file remain two call results, not a synthesized net diff.

For write, displaying the reported content would be sufficient; there is no need to read the previous file and manufacture a diff.

Keep the scope narrow

Reuse provider-reported output, the existing on-demand detail request, and the current Diff renderer. Do not add change tracking for bash, external programs, or nested codemode edits. No directory scans, snapshots, automatic Git initialization, multi-repository inventory, new checkpoint backend, or restore support is proposed.

This is useful in non-Git projects, but the distinction also matters in Git projects: a per-call edit result and a complete checkpoint turn diff answer different review questions.

Prototype and direction

A prototype branch is available to make the proposal concrete. No PR has been opened, and no approval is assumed.

Would this provider-output-only review path fit T3 Code's direction? I would welcome guidance on the entry point and scope before opening a PR.

Prototype implementation assisted by GPT 6.1 Sol using Pi.