[juliusmarminge]

Problem

A relative Markdown file link written with Windows separators, such as [Windows path](src\Example.cs), renders as a plain link. Clicking it opens a browser tab at /<environment>/src%5CExample.cs instead of the file. The same link written as [Slash path](src/Example.cs) renders as a file chip and opens the file viewer. To reproduce on main: open a project that contains src/Example.cs, then have a message contain both links. It happens in agent replies and in user messages, on any host.

Change

parseMarkdownFileLink in packages/shared first parses the destination exactly as main does. If that fails, and the path is relative and contains a backslash, it parses again with \ read as /. src\Example.cs, src%5CExample.cs and src\Example.cs:3 then resolve to the same target as their slash forms. Inline code paths already read relative \ as a separator.

Links that already resolved keep their spelling. POSIX file names may contain a backslash, so ./foo%5Cbar.ts still opens foo\bar.ts. Rooted paths (\foo, \\host\share) and Windows drive paths are never rewritten, so the network-path guard sees them unchanged. Web and mobile both call this parser, so both get the fix.

Scope and approval

Fixes #33625

Verification

Focused tests:

• packages/shared/src/markdownLinks.test.ts
  • resolves the relative link %s against a windows cwd: three cases (src\Example.cs, src%5CExample.cs, src\Example.cs:3) fail on main with expected null to be 'C:\repo\src\Example.cs' and pass with the fix.
  • keeps a backslash in a relative link that already names a file: guards the POSIX literal-backslash case.
  • Two parser cases cover rooted paths: \foo.ts is still not a file link, and /\server\share\x.ts keeps its spelling.
• vp test run passed on markdownLinks, fileLinks, threadFindText, web markdown-links and mobile markdownLinks: 108 tests.
• Head 545a290 merges current main (16a6c1c). markdownLinks.ts and its web and mobile callers are unchanged since the captures at 7cbf20e. vp run check:changed passed on 545a290 (format, lint, knip, typecheck, 64 tests).
• Review on 545a290: two independent reviewers, both MERGE with no confirmed findings. Their differential runs over 50,000 and 637,420 generated links found no change for any link that parsed before. The parser stays linear on 3000-token malformed input (under 1 ms).
• Proof audit on 545a290: sufficient. The captures below cover the affected web rows; the rows listed under Not checked are waived.

Real app: web dev server on a fresh database, project with src/Example.cs, and one thread whose user message and agent reply both contain the two links.

	Before (bbdc7dc)	After (7cbf20e)
Backslash link

File-name label and non-media embed, in one user message: W2: [Example.cs](src\Example.cs) W8: ![file](src\Example.cs) control: [Example.cs](src/Example.cs). Before is on main 53bcb9a, the current merge-base; after is on 7cbf20e.

	Before (53bcb9a)	After (7cbf20e)
Message (crop)
Full window	before	after

What else changed, visible in the captures:

• Relative links with \ that fail the first parse now render as file chips and open the file viewer. This applies to the link label, the file-name label and a non-media embed (which showed "Image unavailable" before).
• Not from this PR: in the full-window pair the sidebar, file-panel state and timestamps differ. The after server's database also holds the thread from the first row, and the two runs were separate sessions.
• Nothing else changes in code: links that already parsed keep their exact result.

Notes on the evidence:

• Before: the backslash link is a plain link in both the user message and the agent reply, next to the slash chip.
• After: both links are Example.cs chips in both messages, and the file viewer shows src/Example.cs with its contents. These stills show how each link is classified and the end state; they are not a recording of the clicks.
• Control (before): the slash chip with the file panel open; the panel is still loading in this capture: capture.
• Scripts and matrix: the parser driver is parse-driver.mts. The fixture matrix is matrix.md. It was derived on an earlier revision that always rewrote relative backslashes. A second audit pass re-checked its waivers against the final code.

Not checked:

• Click behaviour. No recording was made. The stills above show classification and end state only.
• A Windows host. Resolution against a Windows workspace is covered by the C:\repo unit cases, and the fixed link takes the same path as the slash link.
• The mobile client. It calls the same shared parser, so the link is now a file chip there too; checked by code reading only.
• Image and media embeds (![](img\a.png)). They still resolve through markdownDestinationHostPath and keep their backslashes. A non-media embed now gets the existing file-chip fallback (captured above).

AI-assisted; verified with the tests and tools listed above.

[macroscopeapp]

Approvability

Verdict: Approved at e18682c

Macroscope's review found this PR approvable — Relative Windows-style Markdown links now use existing file-link handling rather than ordinary link navigation. Previously recognized paths and rooted-path safeguards remain unchanged, keeping the change narrowly scoped.

No code changes detected at 545a290. Prior analysis still applies.

^{You can add or adjust custom eligibility rules. Learn more.}

[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	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	21.5 KiB	21.5 KiB	0 B (0.0%)	24.4 KiB	✅
Codex	Live turn messages	1	1	0 (0.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.9 KiB	21.9 KiB	0 B (0.0%)	24.4 KiB	✅
Claude	Live turn messages	1	1	0 (0.0%)	8	✅

Baseline: 16a6c1c · PR result: 545a290 · 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: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

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

[coderabbitai]

No actionable comments were generated in the recent review.

Walkthrough

The Markdown file-link parser now retries eligible paths with backslashes as forward slashes when parsing the original path fails. Tests cover backslash path parsing and relative-link resolution against a Windows working directory.

Changes: Windows file links

Layer / File(s)	Summary
Parse and resolve Windows file links packages/shared/src/markdownLinks.ts, packages/shared/src/markdownLinks.test.ts	The parser first tries the original path, then retries eligible paths with converted separators. Tests cover UNC-style paths, rejected single-backslash filenames, and relative-link resolution with Windows paths.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Low

Suggested reviewers: t3dotgg

Merge Risk: Minimal · up to e1868

No merge-blocking risk is established from the available evidence.

Pre-merge checks: 3 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Description check		The description covers the problem, change, and focused verification in detail. The scope section links issue #33625 but does not include explicit maintainer approval of the direction and scope or exp…	Add the maintainer approval comment for the linked issue or discussion. If this is a small, focused fix that needs no prior approval, explain why it qualifies as an obvious bug fix.

Passed checks: 3 passed

Check name	Status	Explanation
Title check		The title clearly and concisely describes the fix for relative Windows file links.
Linked Issues check		Issue #33625 requires relative Windows-style Markdown links to resolve to the workspace file like slash-separated links. parseMarkdownFileLink first preserves paths that already parse, then retries …
Out of Scope Changes check		The pull request changes only packages/shared/src/markdownLinks.ts and its tests. The parser fallback and regression cases directly support issue #33625. No unrelated changes are present in the revi…

Full details: Linked Issues check

Explanation

Issue #33625 requires relative Windows-style Markdown links to resolve to the workspace file like slash-separated links. parseMarkdownFileLink first preserves paths that already parse, then retries an unrooted relative path with backslashes treated as separators. The tests cover slash, backslash, percent-encoded backslash, and line-suffixed links against a Windows working directory. They also cover preserving a literal backslash in an already-resolved relative filename and leaving rooted paths unchanged.

Full details: Out of Scope Changes check

Explanation

The pull request changes only packages/shared/src/markdownLinks.ts and its tests. The parser fallback and regression cases directly support issue #33625. No unrelated changes are present in the reviewed diff.

Full details: Description check

Explanation

The description covers the problem, change, and focused verification in detail. The scope section links issue #33625 but does not include explicit maintainer approval of the direction and scope or explain why this fix qualifies as an obvious bug exemption.

Resolution

Add the maintainer approval comment for the linked issue or discussion. If this is a small, focused fix that needs no prior approval, explain why it qualifies as an obvious bug fix.

Finishing Touches

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Recent review info

Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: fix/issue-33625
• File: .coderabbit.config.ts
• Commit: e18682c
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Team
• Run ID: 40d9cd45-a132-40a4-8155-553356faa0fa

Commits

Reviewing files that changed from the base of the PR and between 53bcb9a and e18682c.

Files selected for processing: 2

• packages/shared/src/markdownLinks.test.ts
• packages/shared/src/markdownLinks.ts

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