Ralph Loop plugin: stop-hook.sh fails on Windows - cat command not found

[chashamm]

Bug Description

The Ralph Loop plugin's stop-hook.sh fails on Windows with Git Bash because the cat command is not found in PATH when the hook executes.

Error Message

Stop hook error: Failed with non-blocking status code:
  hooks/stop-hook.sh: line 10: cat: command not found

Root Cause

Line 10 of hooks/stop-hook.sh uses:

HOOK_INPUT=$(cat)

When Claude Code executes bash scripts on Windows, the PATH doesn't include Git Bash's /usr/bin directory where cat resides.

Suggested Fix

Use the full path to cat:

HOOK_INPUT=$("/usr/bin/cat")

Environment

• OS: Windows 10/11
• Shell: Git Bash
• Claude Code version: Latest

Workaround

Manually edit the cached hook script:

sed -i '10s/.*/HOOK_INPUT=$("\/usr\/bin\/cat")/' ~/.claude/plugins/cache/claude-plugins-official/ralph-loop/*/hooks/stop-hook.sh

[github-actions]

Found 3 possible duplicate issues:

1. Ralph Loop plugin: stop-hook.sh fails on Windows - cat command not found #16559
2. [Ralph Wiggum Plugin] Windows 11 Compatibility Fixes for Stop Hook #16377
3. [BUG] Shell snapshots export empty PATH on Windows (Git Bash), breaking command execution #15128

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🤖 Generated with Claude Code

[chashamm]

👎

[ccjwc]

Related Windows issue: On Windows with PowerShell, the .sh hook opens in VS Code (or the default .sh file handler) instead of executing.

Root cause: Windows doesn't know how to execute .sh files natively - it defers to file associations.

Workaround: Edit the plugin's hooks.json to explicitly invoke bash:

"command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh\""

This relies on bash being in PATH (typically works if Git Bash is installed and added to PATH).

After editing, clear the plugin cache (.claude/plugins/cache/claude-plugins-official/ralph-loop/) and restart Claude Code.

Suggested proper fix: The plugin itself should handle Windows compatibility - either by detecting the platform or by having Claude Code resolve .sh execution automatically on Windows.

[Grips001]

Workaround

For those facing this issue: manually edit the hooks.json file in the plugin cache after installation.

Note: Plugin updates may overwrite this fix.

---

Details

On Windows, the stop hook fails to execute because the hooks.json specifies the shell script path directly without explicitly invoking bash:

"command": "${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh"

Windows does not recognize the #!/bin/bash shebang and instead attempts to open the .sh file with a default application (such as File Explorer or a text editor) rather than executing it.

---

Fix

Explicitly invoke bash in the command:

"command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh\""

---

File Location

~/.claude/plugins/cache/claude-plugins-official/ralph-loop/<version>/hooks/hooks.json

---

Full Corrected hooks.json

{
  "description": "Ralph Loop plugin stop hook for self-referential loops",
  "hooks": {
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh\""
          }
        ]
      }
    ]
  }
}

[oinani0721]

I submitted a comprehensive fix for this issue. PR Ready: anthropics/claude-plugins-official#127 - Fixes PATH (including cat/jq not found), UTF-8 encoding, cygpath, output format, and race conditions. No manual hooks.json editing needed. Tested on Windows 11. See #16377 for details.

[oinani0721]

The "cat command not found" issue is caused by missing PATH in Git Bash subprocess.

Fix: Add this at the beginning of your hook scripts:

export PATH="/usr/bin:/bin:/mingw64/bin:$PATH"

This also fixes jq, rm, and other command not found errors.

Full solution with all Windows 11 fixes: #9758

Related: #16377 #17257 #14817