[Bugs] On Windows, agent-merge skill scripts run under WSL bash and fail (bundled gh/jq not on WSL PATH)

[torumakabe]

Short summary

On Windows, the agent-merge skill runs its helper script with bare bash (e.g. bash check-merge-conditions.sh <owner> <repo> <pr>). On a standard Windows dev box that has WSL installed, bash resolves to C:\Windows\System32\bash.exe (the WSL launcher), so the script executes inside the WSL distro, where the Copilot-bundled gh and the user's jq are not on PATH. The script fails immediately with No such file or directory / exit 127, so agent-merge cannot evaluate merge conditions.

Affected version or release

• GitHub Copilot app: 0.2.27
• Copilot CLI: 1.0.60
• OS: Windows 11 Enterprise (10.0.26200)
• WSL: installed (default distro Ubuntu-22.04)
• Git for Windows: 2.53.0.windows.3 (Git Bash present at C:\Program Files\Git\bin\bash.exe but NOT on PATH, which is the Git for Windows default)

What happened?

When agent-merge follows the skill instructions and runs bash check-merge-conditions.sh ...:

/bin/bash: C:Users...app-skills\agent-merge\check-merge-conditions.sh: No such file or directory
# exit 127

The script never runs because:

1. bash resolves to the WSL launcher (System32\bash.exe), not Git Bash.
2. Inside WSL, the Copilot-bundled gh (%LOCALAPPDATA%\copilot-desktop-gh-*\gh) and the user's jq (mise shim) are not available, so even when the path is corrected the script's gh/jq calls fail.

Confirmed root cause on this machine: the only bash.exe entries on PATH are the two WSL launchers (System32, WindowsApps); C:\Program Files\Git\bin is intentionally not on PATH (Git for Windows default). So bare bash -> WSL is the out-of-the-box outcome.

Why this is not environment-specific

This reproduces for the common configuration class "Git for Windows (default install) + WSL installed", not a one-off misconfiguration:

• Git for Windows deliberately keeps bash off PATH to avoid shadowing system tools.
• WSL places bash.exe in System32.
• Therefore bare bash -> WSL is the default behavior for a large population of Windows dev machines, and the skill always invokes bare bash.

It happens on every agent-merge run/session on such a machine.

Workaround

Invoking the script through Git Bash explicitly works, because Git Bash inherits the Windows PATH and can see the bundled gh and the jq shim:

& "C:\Program Files\Git\bin\bash.exe" -lc "/c/Users/.../agent-merge/check-merge-conditions.sh <owner> <repo> <pr>"

(With Git Bash the WSL/PATH problem is gone; a separate Failed to fetch requested reviewers / exit 2 can still occur from the script's reviewer fetch, but that is a different layer.)

Suggested fixes

1. When running skill .sh scripts on Windows, prefer Git Bash (C:\Program Files\Git\bin\bash.exe) over a bare bash that resolves to WSL.
2. Or ensure the interpreter used for skill scripts can see the Copilot-bundled gh and jq.
3. Or provide a PowerShell-native execution path / fallback for these skills on Windows.

Related

• Support Git Bash copilot-cli#508 (Support Git Bash)
• Copilot CLI uses Unix-only commands on Windows copilot-cli#2981 (Copilot CLI uses Unix-only commands on Windows)