cwd normalisation from #377 misses WSL /mnt/<drive> paths, so session/list cannot find sessions it just created

[ycheoo]

Summary

#377 made cwd comparison case-insensitive for Windows paths. The normalisation only recognises native Windows forms, so /mnt/c/... paths — what a Windows client passes when the agent runs inside WSL — still compare case-sensitively. Because Codex stores those paths lowercased in its thread index, session/list cannot find a session created moments
earlier with the very same cwd string.

Environment

• @agentclientprotocol/codex-acp 1.6.2 (vendored @openai/codex 0.148.0, x86_64-unknown-linux-musl)
• WSL2, Ubuntu 22.04, Node 22.23.2
• cwd on a DrvFs mount, e.g. /mnt/c/Users/Me/Notes/MyVault

Reproduction

Over stdin, keeping stdin open for each reply:

1. initialize
2. session/new → {"cwd": "/mnt/c/Users/Me: []} — succeeds
3. session/list → {"cwd": "/mnt/c/Users/Me/Notes/MyVault", "cursor": null} — 0 sessions
4. session/list → {"cwd": "/mnt/c/users/me/notes/myvault", "cursor": null} — returns the session from step 2

Only the casing differs between steps 3 and

Cause

listSessions filters with arePathsEqual(thread.cwd, requestedCwd). thread.cwd comes from the Codex thread index, which stores /mnt/ paths lowercased. The same session ends up recorded twice with different casing:

Location	cwd
~/.codex/sessions/.../rollout-*.jsonl, payload.cwd	/mnt/c/Users/Me/Notes/MyVault
~/.codex/state_5.sqlite, threads.cwd	lt`

normalizePathForComparison lowercases only when isWindowsAbsolutePath is true:

function isWindowsAbsolutePath(value) {
  const portableValue = value.replace(/\\/g, "/");
  return /^[A-Za-z]:\//.test(portableValue) || /^\/\/[^/]+\/[^/]+/.test(portableValue);
}

/mnt/c/Users/... matches neither, so it takes the POSIX branch and keeps its capitals, while the stored value has
none.

Paths under /home are unaffected, being lowercase already. WSL is not the cause: getcwd, realpath and
os.path.realpath all preserve the capitals

Suggested fix

Treat /mnt/<drive>/... as case-insensitive too — either by extending shouldComparePathCaseInsensitive with a ^/mnt/[a-z]/ test, or by lowercasing in normalizePathForComparison whenever the path resolves onto a DrvFs mount.

Downstream impact

The Obsidian Agent Client plugin passes the for its "Show current vault only" filter.Under WSL mode that filter is always empty for any vault on a Windows drive.

Note

@agentclientprotocol/claude-agent-acp 0.70.0 shows the same symptom, so the fix may be worth mirroring there.