[Feature]: Surface Claude Edit/Write before/after text in expanded tool entries

[IcTxDiogo]

Summary

Expanded tool entries for Claude Edit/Write calls show file paths but never the changed text — no before/after and no diff. Codex turns already surface unifiedDiff data; the Claude path has no equivalent, so reviewing what an edit actually changed requires leaving T3 or re-reading the file.

Current behavior

• For Claude edits, the expanded entry carries paths/summaries only. The tool input text (old_string/new_string/content) never reaches the UI in any form.
• Checked on stable 0.0.40 and on current main: a code search shows no old_string/new_string/unifiedDiff handling in ClaudeAdapter.ts — unifiedDiff exists only around the Codex/checkpoint paths, which is a different mechanism (turn-level summaries, not per-edit before/after).

Expected behavior

• Expanded Edit/Write entries include a bounded verbatim before/after pair (with a truncation flag when the bound is hit), rendered in the existing expandable work-log row — no new UI surface needed.
• Collapsed rows stay exactly as today.

Repro

1. In a Claude-backed thread, ask the agent to edit any tracked file.
2. Expand the Edit/Write work-log entry.
3. The entry shows paths only; the old/new text is nowhere in the UI although it was present in the tool input.

A per-field bound keeps this consistent with the recent payload-slimming direction. Happy to provide fixtures or help validate a bounded-payload design.

[juliusmarminge]

Triage

Confirmed on current main. Claude Edit/Write expanded work-log rows show paths/summaries only; the tool input text never appears as a reviewable before/after.

This is not a duplicate of #6388 (Bash output never renders). Same general “persisted tool payload doesn’t reach the expanded row” shape, different field and UI.

What the code does today

ClaudeAdapter already attaches the full tool input on item.started / item.updated / item.completed:

data: { toolName, input } // input has file_path, old_string, new_string, content

There is no Claude unifiedDiff / before-after mapping. Codex unifiedDiff is turn-level (turn.diff.updated → checkpoint placeholders), not per-edit.

The drop happens in projectActivityPayload (ActivityPayloadProjection.ts). For non-MCP tools it keeps toolName and path-like keys as data.files, and drops data.input. item.completed still persists the full payload; the wire snapshot does not.

The UI would not show it even if it survived: web (session-logic.ts + MessagesTimeline.tsx) and mobile (threadActivity.ts) only attach toolData for mcp_tool_call. Expanded file-change rows render command / detail / changedFiles. detail is a ~180-char JSON dump of the input, so it is a path prefix, not a before/after pair.

collectChangedFiles also misses Claude’s snake_case file_path (path / filePath only), so paths often survive only via that truncated detail.

Not already in flight

No open PR implements this. Related but not a fix: #7184 (Bash output), #5482 (payload slimming), #9549 (expanded-row cleanup). Closed #5471 (rich transcript / inline diffs) is not a leftover close.

Suggested fix

Treat this as an accepted enhancement. Keep collapsed rows as they are. On expand, show a bounded verbatim before/after (plus a truncation flag) in the existing work-log row — no new surface, no Codex unifiedDiff reuse.

1. Slim file_change input to bounded old_string / new_string / content (and collect file_path).
2. Render that pair in the existing expanded body on web and mobile.
3. Add projection + UI fixtures. Happy to use reporter-provided fixtures for the bound.

Severity: medium UX gap. Type: enhancement.

[bryanpedini]

Note

Written by Claude Opus 5.5 on behalf of Bryan Joshua Pedini (@bryanpedini).

I'd like to widen this beyond Claude Edit/Write: from the thread itself, see what the agent actually changed in any file, for every provider, whether or not the file is in a Git repository.

Today an expanded file_change row shows the path, +N -N and Open diff. Open diff opens the turn diff, which comes from Git checkpoints. Projects that are not Git repositories, threads without a project, and files outside the workspace (a config file under ~/.config, for example) have nothing to show: the panel says "Turn diffs are unavailable because this project is not a git repository." (DiffPanel.tsx#L981)

What main already has (60b35a1e)

1. Adapters already capture a per-edit diff on file_change.

Provider	Field	Source
Codex	diffStr	patch from the file change (CodexAdapterV2.ts#L3654)
OpenCode	oldStr / newStr / diffStr	tool input and completed metadata (toolItems.ts#L105-L118)
ACP	diffStr	diff tool content, #13579 (adapter.ts#L3774)
Claude	diffStr	the tool result text, not old_string / new_string / content (ClaudeAdapterV2.ts#L4964-L4970)

2. The server stores it, bounded to 32 KB. boundFileChangeForStorage (WireProjection.ts#L42-L54), called from ProviderEventIngestor (#L639).

3. Clients never receive it unless the edit failed.

• projectTurnItemForWire drops diffStr / oldStr / newStr (WireProjection.ts#L113-L118).
• projectTurnItemForDetail, the on-demand getTurnItem path, sends file_change back through the wire projection (WireProjection.ts#L201-L203).
• toolItemForDisplay drops them again on the client (presentation.ts#L40-L46).

4. The on-demand detail path already exists, for commands and dynamic tools only. An expanded command_execution or dynamic_tool row fetches the full stored item through getTurnItem (turnItemNeedsDetailFetch → useFetchedTurnItem, bounded to 256 KB). file_change never takes that path (itemDetail.ts#L128-L137), so the inspector renders only path, counts and Open diff (V2ItemInspector.tsx#L284-L308).

Proposal

Extend the existing on-demand detail path to file_change. When a row is expanded, fetch the stored item and render its diffStr (or a diff built from oldStr / newStr) inline, with the same diff renderer the side panel uses. It does not depend on Git, so it covers non-Git projects and files outside the workspace too.

For Claude this also needs the adapter to keep old_string / new_string / content as oldStr / newStr, as suggested in the triage above.

Scope I'm happy with:

• Behind a setting (something like "Show edit diffs in the thread" or a general verbose option), off by default.
• The Diff side panel and Open diff stay exactly as they are.
• Expanded rows only. Collapsed rows and the wire payload stay as today.
• The existing 32 KB storage bound and truncation are fine.

Related

• This discussion's triage ([Feature]: Surface Claude Edit/Write before/after text in expanded tool entries #10970, converted here).
• Show inline file-change diffs in chat timeline tool rows #7428: inline file-change diffs in timeline tool rows, closed without merge.
• fix(server): show diffs for ACP edits that send oldText/newText #13579: ACP oldText / newText → diffStr, merged.
• [Feature]: Show changed files from repositories modified by the agent #12089: edits to repositories outside the workspace are invisible in Changed files / Diff.

Seen on t3code-bin 0.1.0 (Arch Linux), checked against main @ 60b35a1e.