feat(web): open files in containing folder

[t3-code]

1|## problem
2|
3|file link context menus can open files in editors or copy their paths, but cannot reveal them in the host file manager.
4|
5|## fix
6|
7|- add an "Open in folder" action to markdown file chip context menus
8|- route the action through the thread's environment so remote hosts open their own file manager
9|- reveal files with Finder and Windows Explorer, and open the containing directory on Linux
10|- add launcher and websocket routing coverage
11|
12|## testing
13|
14|- GOMAXPROCS=2 pnpm --filter @t3tools/contracts typecheck
15|- GOMAXPROCS=2 pnpm --filter @t3tools/client-runtime typecheck
16|- GOMAXPROCS=2 pnpm --filter t3 typecheck
17|- GOMAXPROCS=1 pnpm --filter @t3tools/web typecheck
18|- GOMAXPROCS=2 pnpm --filter t3 exec vp test run src/process/externalLauncher.test.ts
19|- GOMAXPROCS=2 pnpm --filter t3 exec vp test run src/server.test.ts -t "routes websocket rpc shell.revealInFileManager"
20|
21|model: gpt-5.4
22|harness: t3bot
23|
24|

---

Note

Medium Risk
Spawns host processes from user-supplied paths and branches on SSH/WSL/session env; scope is bounded by capability gating and operate-scope auth, with broad platform test coverage.

Overview
Adds Open in folder for chat markdown file links, wired through a new shell.revealInFileManager RPC and a fileManagerReveal server capability so clients only show the action when the host can reveal paths.

The server’s external launcher now spawns the OS file manager with platform-specific behavior (Finder -R, Explorer /select,, Linux xdg-open on the parent folder), including WSL-without-display via explorer.exe and UNC paths. File-manager availability is gated on graphical sessions and suppressed for headless Linux, SSH, and Windows service contexts.

The web UI routes reveals through the thread’s environment, extends file-link context menus, and tightens markdown link handling (richer destination parsing, AST tagging so only real markdown links become file chips—not raw HTML or nested inline-code false positives).

^{Reviewed by Cursor Bugbot for commit bae4628. Bugbot is set up for automated code reviews on this repo. Configure here.}

40|
41|

Note

Add 'Open in folder' file reveal action to chat file links

• Adds a new shell.revealInFileManager WebSocket RPC that spawns the OS file manager to reveal or open the containing folder of a file path.
• Server advertises a fileManagerReveal capability; the UI gates the 'Open in folder' context menu item on this capability, connection phase, and available editors.
• Handles cross-platform behavior: macOS uses open -R, Windows uses explorer /select,, Linux uses xdg-open on the containing folder, and WSL without a display uses explorer.exe with UNC paths.
• File manager availability is suppressed for headless, SSH, and Windows service sessions.
• Improves markdown link parsing to support angle-bracketed destinations, balanced parentheses, spaces, and escapes, and distinguishes markdown-generated anchors from raw HTML anchors to avoid false file link matches.

^{Macroscope summarized bae4628.}

58|

1|## request provenance
2|
3|- requested by: @MatthewFeroz
4|
5|
6|

[macroscopeapp]

Approvability

Verdict: Needs human review

This PR introduces a new feature ('open files in containing folder') with a new RPC endpoint, authorization scope, server capability, cross-platform file manager integration, and user-facing context menu functionality. New features introducing user-facing behavior and authorization changes warrant human review.

No code changes detected at bae4628. Prior analysis still applies.

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[t3-code]

updated the review fixes: open in folder is first and only appears when the file’s connected environment advertises both the reveal rpc and an available file manager. added focused menu-order and visibility tests.

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	11.3 KiB	11.3 KiB	+7 B (+0.1%)	15.1 KiB	✅
Codex	Thread snapshot wire	5.5 KiB	5.5 KiB	−4 B (−0.1%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	5.9 KiB	5.9 KiB	+11 B (+0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	49.7 KiB	49.7 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	16	16	0 (0.0%)	21	✅
Claude	Total thread wire	11.3 KiB	11.3 KiB	+10 B (+0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	5.5 KiB	5.5 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	5.9 KiB	5.9 KiB	+8 B (+0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	50.6 KiB	50.6 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	16	16	0 (0.0%)	21	✅

Baseline: 8c628f1 · PR result: bae4628 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 94.6 KiB
• Claude decoded thread snapshot: 95.4 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[t3-code]

reviewed the full diff, existing review threads, and the result merged onto current main (e321667b1). i found no blocking issues.

verified on the merged tree:

• contracts, client-runtime, server, and web typechecks
• external launcher tests: 17 passed
• markdown and file-link menu tests: 51 passed
• rpc routing test: 1 passed
• authorization and environment capability tests: 7 passed
• targeted lint, formatting, and git diff --check

all github ci on 50f611eaf is green. the pr is technically mergeable. this is a comment review rather than a human approval, so a maintainer approval may still be required by policy.

[t3-code]

correction to my earlier review: two blocking edge cases were found and reproduced after a deeper parser/platform pass.

1. apps/web/src/markdown-links.ts:181-214: the custom href scanner parses markdown-looking text inside inline code. [see \x`](src/real.ts)renders one link tosrc/real.ts, but the scanner returns only fake.ts. ChatMarkdown` therefore misses the real file link and routes it as a normal link.

2. apps/server/src/process/externalLauncher.ts:241-260: WSL uses Explorer only when DISPLAY and WAYLAND_DISPLAY are absent. Standard WSLg sets those variables, so the code chooses Linux xdg-open instead of the available Windows Explorer. This can hide the action when xdg-open is absent or invoke a handler that cannot reveal the file. Current WSL coverage tests only the non-WSLg environment.

these should be fixed before merge. the malformed-destination performance concern was also tested, but i could not reproduce quadratic behavior in the actual implementation, so i am not including it as a finding.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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[t3-code]

closing in favor of #6463, the newer and broader implementation with authorization, launcher, contract, client, and test coverage.