Windows: ${CLAUDE_PLUGIN_ROOT} backslashes stripped when passed to bash hooks

Description

On Windows, when a plugin hook uses ${CLAUDE_PLUGIN_ROOT} in its command, the backslashes in the Windows path are stripped when the command is passed to bash.

Steps to Reproduce

1. Install the superpowers plugin on Windows
2. Start a new Claude Code session
3. Observe the startup hook error

Expected Behavior

The path should be correctly passed to bash. Either:

• Convert backslashes to forward slashes (bash on Windows handles these)
• Properly escape the backslashes

Actual Behavior

From debug log:

Hook SessionStart:startup (SessionStart) error:
/bin/bash: C:Userspunee.claudepluginscacheclaude-plugins-officialsuperpowers4.1.1/hooks/session-start.sh: No such file or directory

The path C:\Users\punee\.claude\plugins\cache\claude-plugins-official\superpowers\4.1.1 becomes C:Userspunee.claudepluginscacheclaude-plugins-officialsuperpowers4.1.1 (all backslashes removed).

Workaround

Manually edit the plugin's hooks.json to use a hardcoded path with forward slashes:

"command": "C:/Users/username/.claude/plugins/cache/claude-plugins-official/superpowers/4.1.1/hooks/session-start.sh"

Environment

• Claude Code version: 2.1.29
• OS: Windows 11
• Bash: GNU bash 5.2.37 (Git Bash)

Additional Context

The hooks.json in superpowers plugin uses:

"command": "${CLAUDE_PLUGIN_ROOT}/hooks/session-start.sh"

This variable interpolation works on macOS/Linux but fails on Windows due to the backslash handling.