Problem
scripts/check-drive-root-litter.sh is the post-hoc detector for the Windows path-emission defect that docs/conventions/windows-path-emit/README.md owns: a POSIX path handed to a Windows-native consumer resolves against the current drive and creates a phantom directory at a volume root.
It only matches a drive-root directory whose name is a single letter that is itself a mounted drive. That shape catches the /d/dir → D:\d class, but it is blind to the /tmp class.
Observed miss
A disk audit of C:\ on 2026-08-30 found an empty C:\tmp\tmp.rSFIkHm5DO, created at 14:15:56.
Root cause of the artifact: plugins/source-control/skills/worktree/context/create.md:88 runs a bare mktemp -d and prints the result. TMPDIR is unset on that machine and GNU mktemp reads TMPDIR only, so the printed string is the POSIX literal /tmp/tmp.rSFIkHm5DO while the real directory lives under %TEMP%. That string round-trips through the model into a native Write tool call, and node.exe resolves the leading / against the current drive.
The detector scored it zero, because tmp is not a single letter. Nothing on the host reported it.
Why the sibling nets did not catch it either
plugins/guardrails/hooks/block-windows-drive-tmp.sh reads .tool_input.command and is registered for Bash and PowerShell, so a Write tool call carrying file_path never reaches it.scripts/check-shell-portability.sh is correctly out of charter; its axis is GNU-vs-BSD userland divergence, and an MSYS path literal is valid GNU shell everywhere.
Proposed fix
Give the detector a known-temp-sink-name class at a drive root, reusing block-windows-drive-tmp.sh's existing sink vocabulary rather than inventing a second list, so the two grow together.
Constraints that must hold: the single-letter class stays byte-equivalent, the cwd-containment false-positive guard extends to the new class, the non-Windows no-op stays first and reported, exit codes stay 0/1/2, and the detector stays advisory per docs/adr/0003-verification-guards-earn-default-on-by-measured-precision.md (it has no measured precision yet).
Problem
scripts/check-drive-root-litter.shis the post-hoc detector for the Windows path-emission defect thatdocs/conventions/windows-path-emit/README.mdowns: a POSIX path handed to a Windows-native consumer resolves against the current drive and creates a phantom directory at a volume root.It only matches a drive-root directory whose name is a single letter that is itself a mounted drive. That shape catches the
/d/dir→D:\dclass, but it is blind to the/tmpclass.Observed miss
A disk audit of
C:\on 2026-08-30 found an emptyC:\tmp\tmp.rSFIkHm5DO, created at 14:15:56.Root cause of the artifact:
plugins/source-control/skills/worktree/context/create.md:88runs a baremktemp -dand prints the result.TMPDIRis unset on that machine and GNUmktempreadsTMPDIRonly, so the printed string is the POSIX literal/tmp/tmp.rSFIkHm5DOwhile the real directory lives under%TEMP%. That string round-trips through the model into a nativeWritetool call, andnode.exeresolves the leading/against the current drive.The detector scored it zero, because
tmpis not a single letter. Nothing on the host reported it.Why the sibling nets did not catch it either
plugins/guardrails/hooks/block-windows-drive-tmp.shreads.tool_input.commandand is registered for Bash and PowerShell, so aWritetool call carryingfile_pathnever reaches it.scripts/check-shell-portability.shis correctly out of charter; its axis is GNU-vs-BSD userland divergence, and an MSYS path literal is valid GNU shell everywhere.Proposed fix
Give the detector a known-temp-sink-name class at a drive root, reusing
block-windows-drive-tmp.sh's existing sink vocabulary rather than inventing a second list, so the two grow together.Constraints that must hold: the single-letter class stays byte-equivalent, the cwd-containment false-positive guard extends to the new class, the non-Windows no-op stays first and reported, exit codes stay 0/1/2, and the detector stays advisory per
docs/adr/0003-verification-guards-earn-default-on-by-measured-precision.md(it has no measured precision yet).