fix(chat): resolve Claude config store on Windows

[David-Sousa-Web]

Problem

A Claude Code pane launched on Windows with a custom CLAUDE_CONFIG_DIR stores its native session and transcript outside ~/.claude.

The existing custom-store resolution introduced in #504 discovers the running Claude process's config directory on Linux and macOS, but Windows has no equivalent path. As a result, the pane falls back to ~/.claude, the transcript is not found, and Chat shows Conversation unavailable while Terminal still works.

Example layout:

~/.claude            default account (herdr's SessionStart hook installed)
~/.claude-account2   second account, started with CLAUDE_CONFIG_DIR=%USERPROFILE%\.claude-account2

Root cause

Measured on Windows 10 with herdr 0.9.3 and Claude Code 2.1.292. Three gaps stack up:

1. The pane's Claude process is never found. herdr's pane.process_info reports a Windows Claude as name: "claude.exe" with a backslash argv0 (C:\…\.local\bin\claude.exe). The filter in claudeTranscriptPath only matched claude or /claude, so only stayed undefined. Neither the config-dir lookup nor the PID-record lookup ran.
2. processClaudeConfigDir has no Windows branch. It reads /proc/<pid>/environ on Linux and ps -E on macOS. Windows lets no other process read Claude's environment.
3. claudeProcessSession returns null on anything but Linux and macOS. A store without herdr's hook (the usual case for a second account) has no session id, so the pane ends at no_session_id.

Change

• isClaudeProcess (claude-store.ts) also accepts claude.exe and backslash paths. It replaces the inline filter in conversation.ts; Linux and macOS matches are unchanged.
• On Windows, processClaudeConfigDir uses the store that holds the process's own live sessions/<pid>.json. It looks in ~/.claude, the server's CLAUDE_CONFIG_DIR and each ~/.claude-* directory (one readdir of home, nothing recursive; the same sibling set usage.ts already knows). It answers only when exactly one store has a valid record, and otherwise falls back to the default store as before.
• claudeProcessSession runs on Windows, with the same record checks (size bound, pid, kind: "interactive", UUID sessionId). The stale-PID check is kept. On Windows Claude writes procStart as a FILETIME (100 ns ticks since 1601). That is compared, to the millisecond, with the start the existing Windows process table reports (recentProcessTable, shared with gjc and cached for 5 s), so a leftover record from a reused PID is refused. A table that cannot be read refuses the record.
• A Windows miss is not cached, because Claude writes its record as it starts. A found store is cached for PROCESS_DIR_TTL_MS, as on Linux and macOS.
• Linux and macOS behavior is unchanged. platform and table are injectable parameters with defaults (as in gjcPidUnderShell), so the Windows branch is unit-tested on any OS.
• Nothing new reaches the browser, no credential file is opened (only sessions/<pid>.json), and there are no new dependencies.

Validation

Live, on Windows (paneConversation against real herdr panes, server env as plugin.ps1 sets it):

pane store	main	this branch
~/.claude (hooked), 2 panes	claude-transcript	claude-transcript (same turns)
~/.claude-* (no hook), 4 panes	no_session_id → Conversation unavailable	claude-transcript

The Chat view was also checked in the browser on that PC, against a server from this branch on a separate port with a temporary state dir: a second-store Claude pane shows its conversation, where the installed main build shows Conversation unavailable.

Linux (Ubuntu 24.04 under WSL, Bun 1.4.2, clean clones of main and of this branch):

• bun run generate:types --check, bun run typecheck and bun run build pass on both.
• HERDR_TEST_MODE=unit bun test ./server/claude-store.test.ts: 19/19 on main, 33/33 here.
• bun run test:unit: 1680 pass here. The only failures on either tree are in scripts/install-star.test.ts ("install.sh at a terminal"), which is flaky the same way on both: rerun twice, it went 22/22, then 21/22, on main and on this branch alike. It is unrelated to this change.

Windows (Bun 1.4.2): claude-store.test.ts has 22 passing, and the one failure (chmod permissions) fails identically on main. windows-native.test.ts has 4/4 passing, including the new real-PC test. conversation.test.ts has 48/48 passing.

Tests added:

• server/claude-store.test.ts, "a Windows Claude's store" (runs on any OS, with a temp home whose path contains spaces, the server's CLAUDE_CONFIG_DIR cleared, and the process table handed in):
  • herdr's Windows process shape is recognized as Claude, and look-alikes are not.
  • A record in ~/.claude keeps the default store.
  • A record in ~/.claude-* selects that store, and with the same session id and project in both stores, the transcript comes from the pane's own store.
  • A stale record of the same PID in ~/.claude loses to the live one.
  • These records are ignored: another PID, a reused PID (1 ms off), macOS-style procStart, no procStart, kind: "sdk", a non-UUID session id, torn JSON, an oversized record, and a process missing from the table.
  • ~/.claude-* entries that are files, empty directories, or stores without a record are harmless, and so is a missing home.
  • Two stores both claiming the process select none.
  • A miss is looked up again once the record appears.
• server/windows-native.test.ts (real Windows only, like the existing tests there): a record carrying this process's real FILETIME start, from PowerShell, is accepted and selects its ~/.claude-* store. A record 1 ms off is refused.

Existing Linux and macOS tests in claude-store.test.ts and claude-session.contract.test.ts are unchanged.

Notes

• O_NOFOLLOW and O_NONBLOCK do not exist on Windows (Node and Bun leave them undefined), so the record read there has no "no symlink" guard. The record lives in the user's own store, and creating a symlink on Windows needs privilege or Developer Mode.
• This fixes the Windows path only. Panes that herdr reports with a Claude foreground process were verified; I did not add a process-table fallback for a Windows herdr that would list only the shell.

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📝 Summary

Summary by CodeRabbit

• Bug Fixes
  • Fixed chat session detection on Windows when Claude Code uses a separate configuration directory, helping chats open the matching session.
  • Improved recognition of Windows Claude Code processes and matching sessions to the process that started them.
  • Prevented stale or invalid session records from being used. When process inspection fails or a matching store can’t be identified, chat uses the default Claude configuration directory.

Walkthrough

The change adds Windows Claude process recognition, config-store discovery, and session validation using PID records and process start times. Conversation lookup uses the shared process predicate and resolved config directory. Tests cover store selection, invalid or stale records, retries, and FILETIME comparisons.

Changes

Windows Claude Store Discovery

Layer / File(s)	Summary
Process identification and session validation server/claude-store.ts, server/claude-store.test.ts, server/windows-native.test.ts	A shared predicate recognizes Claude executable names, including Windows executable paths. Windows session lookup compares the PID record’s start time with the process table. Tests cover accepted process descriptions and session-record validation.
Config-store discovery and conversation lookup server/claude-store.ts, server/claude-store.test.ts, server/conversation.ts, server/windows-native.test.ts, CHANGELOG.md	Windows lookup searches candidate Claude stores and selects a store only when one has a matching live PID record. Conversation lookup uses the shared predicate and passes the home directory to config-store resolution. Tests cover store selection, misses, and retries. The changelog describes the Windows fix.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 3f12a

No concrete merge-blocking risk remains; the Windows lookup path now supplies the profile directory needed for custom Claude stores.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 73.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 15 functions across 4 files. (1 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the problem, root cause, implementation, scope, security considerations, and validation results. It includes the required Change and Validation sections and provides r…
Title check	✅ Passed	The title clearly and concisely identifies the primary change: fixing Claude chat config-store resolution on Windows.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 73.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 15 functions across 4 files. (1 skipped: 1 unsupported.)

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Actionable comments posted: 2

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Inline comments:
Review comments at @server/claude-store.ts:
- Around line 26-28: Update the Claude executable matching near the `executable`
regex to recognize Windows executable names case-insensitively while preserving
POSIX case-sensitive behavior; also update the `.claude-` sibling-store prefix
check at server/claude-store.ts lines 70-70 to match case-insensitively. Make
both changes in server/claude-store.ts lines 26-28 and 70-70, respectively.

Review comments at @server/conversation.ts:
- Line 756: Resolve the home directory with the OS home-directory API when
`HOME` is absent. In `server/conversation.ts` at line 756, pass the resolved
home to both `processClaudeConfigDir` and `defaultClaudeConfigDir`; in
`server/claude-store.ts` at line 125, use the OS home as the default when the
exported lookup receives no home argument.

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• CHANGELOG.md
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• server/claude-store.ts
• server/conversation.ts
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[devswha]

Thanks for this. The root-cause write-up matches the code, and the fix fits how the Linux and macOS paths already work. I reviewed head b7709ba against v0.4.0 (aca94ee). It merges cleanly there and on current main, and I found no failing scenario. One thing needs fixing before merge (the changelog section), and the rest are notes.

What I checked

• Process match. isClaudeProcess replaces the inline filter in claudeTranscriptPath with the same POSIX behavior (claude or /claude, case-sensitive) and adds claude.exe and backslash paths, matched without case. The look-alike cases in the test are the right ones.
• PID-record check. fileTimeMs divides the FILETIME by 10,000 with BigInt, which truncates. The table's Started is ([DateTimeOffset]$_.CreationDate).ToUnixTimeMilliseconds(), which also truncates. So the millisecond equality is stable and does not depend on rounding. A table that cannot be read gives no row, and the record is refused, which fails closed.
• Store selection. Stores are deduplicated by resolve(...).toLowerCase(), a store answers only when exactly one holds a valid record, and a stale record for a reused PID in another store is refused by its start time. The "two stores both claim it" case falls back to the default store as before.
• O_NOFOLLOW / O_NONBLOCK. They are undefined on Windows and coerce to 0 in the bitwise OR, so the open call is valid there. You already describe the missing symlink guard, and I agree it is acceptable for a file inside the user's own store.
• No contract change. Nothing new reaches the browser, so no shared/protocol.ts, contract-test or demo-transport change is needed.

Tests I ran on the head (Linux): claude-store, conversation and windows-native unit files: 82 pass, 4 skipped (the Windows-only ones), 0 fail. I could not run the Windows-only test or the live Windows check here, so those rest on your report.

To fix

• CHANGELOG section. The branch was cut before 0.4.0 was released. After a merge with main the entry sits inside ## [0.4.0] - 2026-10-08 (after the #525 line), which is a released section. Please move it under ## [Unreleased] → ### Fixed.

Notes

• A Windows miss is never cached. That is right while Claude is starting. But a Claude that never writes a record any store accepts (an older version without procStart, or kind other than interactive) repeats readdir(home) plus one open per store on every conversation poll, for as long as the pane is open. The process table is cached for 5 s, so the cost is small. A short negative TTL (a few seconds) would bound it without losing the startup case. Not blocking.
• A bare Claude with no .exe and no backslash is still matched case-sensitively on Windows, because the case-folding is keyed on the text looking like a Windows name. herdr reports claude.exe there, so I do not think it can happen. I mention it only so the rule is a known choice.
• Relation to #518. That issue is about Codex on Windows (\\?\-prefixed rollout paths and a missing session id after codex resume). This PR is about Claude's store, so it does not address #518 and should not close it.
• CI. Only CodeRabbit has run. Fast checks and Integration and browser wait for maintainer approval of the fork run.

bun run check fast (generated types, typecheck, build, unit tests) also passes on this head.

[coderabbitai]

🔇 Additional comments (1)

CHANGELOG.md-24-24 (1)

24-24: 📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win

⚠️ Unverified finding
Verification ran but could not confirm this finding. It is shown for review, not as a verified issue.

Use one spelling variant in the changelog.

This entry uses recognized, while the changelog uses the other spelling variant elsewhere. Match the spelling used elsewhere in the file.

Source: Linters/SAST tools

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[devswha]

I re-reviewed the latest head independently of yesterday's review, and I am merging it.

Since b7709ba

• The code files (server/claude-store.ts, server/conversation.ts, server/claude-store.test.ts, server/windows-native.test.ts) are byte-identical to the head reviewed yesterday. The new commits are a merge of main (f8f09d1, #566) and the changelog move.
• Changelog section: fixed. After git merge-tree --write-tree origin/main, the entry sits under ## [Unreleased], above ## [0.4.0]. I added a maintainer commit, 13b4c2f, that ends the entry with the PR link and credit, as the changelog convention asks. Main moved twice while CI ran (#573, #572), so I merged it in twice. The second merge conflicted in CHANGELOG.md only, and I kept both entries. The head is now 3f12aef on main 407c1a1.

What I checked in the fix

• isClaudeProcess keeps POSIX names case-sensitive (claude, /…/claude) and matches a Windows-looking name (a backslash, or ending in .exe) without case. It is the only filter claudeTranscriptPath uses.
• On Windows, windowsProcessStore answers only when exactly one of ~/.claude, the server's CLAUDE_CONFIG_DIR and the ~/.claude-* siblings holds a live record. It uses allSettled, so an unreadable store counts as not the owner, and two spellings of one directory count once. A Windows miss is not cached, so a record Claude writes after its first poll is picked up.
• Both sides of the start-time check floor to the millisecond: fileTimeMs divides the FILETIME by BigInt and subtracts the 1601 to 1970 offset, and windowsProcessTable reports ToUnixTimeMilliseconds(). A table that cannot be read refuses the record.
• I mutated the code to check that the tests catch these: without the FILETIME epoch offset, 6 of the Windows-store cases in claude-store.test.ts fail; with a Windows miss cached, 2 fail.

What I ran (on 3f12aef, which is main plus this PR)

• HERDR_TEST_MODE=unit bun test ./server/claude-store.test.ts ./server/windows-native.test.ts ./server/conversation.test.ts: 82 pass, 4 skip, 0 fail. The 4 skips are the Windows-only cases. ./server/release-notes.test.ts (which reads the changelog) passes too: 21 pass.
• bun run check fast: all five steps ok. Unit suite: 1714 pass, 5 skip, 0 fail.
• GitHub, on 3f12aef: Fast checks passed, and so did the remote bundle, Windows install and smoke jobs. Integration and browser passed on a rerun of run 37675026759. The first attempt failed only in the browser lane, at scripts/ui-regression.ts "the message sent before the snapshot is a live pending row", a known intermittent failure on main that this change does not touch (it is being fixed separately).

The Windows-only test (windows-native.test.ts, including the new real-PC case) and a live Windows run were not done here; I rely on the Windows results in your description for those. One note for later, not for this PR: as you wrote, a Windows herdr that lists only the shell in foreground_processes (which server/windows-processes.ts records for gjc) would still not find the Claude process; a process-table fallback would cover that.

Thank you for the careful write-up and tests.