claude-code-windows-hook

A minimal, working Node.js template for Claude Code hooks on Windows.

Bypasses the documented bash-hook bugs on Windows Claude Code (.sh scripts not executing, stdin delivered as TTY instead of pipe, shell setting ignored, etc.) by using Node.js 鈥?which Anthropic's official docs already recommend for cross-platform hook authoring, but without providing a concrete working example.

The problem

If you try to write a Claude Code hook on Windows with a bash .sh script, you'll likely hit one or more of these open / unfixed issues:

Issue	Symptom
#24097	.sh hooks trigger a file-association dialog instead of executing
#32930	settings.json shell setting is ignored; hooks hardcoded to /usr/bin/bash
#36156	stdin is delivered as TTY instead of pipe 鈥?cat / jq hang or return empty
#46601	Stop hook stdin bug on PowerShell 5.1 / pwsh 7
#9758	Closed as NOT_PLANNED 鈥?path handling never fixed at the Claude Code level

Existing community workarounds are partial: AutoHotkey scripts that hide bash popup windows, CLAUDE_CODE_GIT_BASH_PATH environment variable tricks, .bashrc + cygpath rewiring. They fix one symptom each but no single recipe that works for all hook types.

The solution

Anthropic's hooks guide notes that hooks invoked via node work uniformly across Windows / Linux / macOS, whereas platform-specific shells do not. This repo is a concrete working implementation of that recommendation, tested on a real Windows 11 Claude Code install. It handles the edge cases that don't appear in the one-line docs mention:

• stdin TTY fallback 鈥?if stdin is a TTY (Windows #36156 bug), skip reading (which would hang) and fall back to CLAUDE_SESSION_ID env var
• MSYS path normalization 鈥?Git Bash passes paths as /c/Users/... but Node's native fs needs C:/Users/...; a small helper normalizes
• Detached worker pattern 鈥?heavy work (API calls, git push) runs in a detached child process so the hook returns in milliseconds and Claude's response is never blocked
• env-based worker communication 鈥?stdin can only be read once; the worker gets its params from env vars set at spawn time

Usage

1. Copy hook-template.mjs to a location on your machine (e.g. ~/.claude/hooks/my-hook.mjs)
2. Replace the runWorker() body with your business logic
3. Register in ~/.claude/settings.json:

{
  "hooks": {
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "node C:/Users/YOU/.claude/hooks/my-hook.mjs"
          }
        ]
      }
    ]
  }
}

Works for Stop, SessionEnd, PreToolUse, PostToolUse, and other hook events. The same pattern applies.

How it compares to alternatives

Approach	Works on Windows?	Caveats
.sh script directly in hook	鉁?	Hits #24097 / #36156 鈥?file association dialog or empty stdin
.sh + CLAUDE_CODE_GIT_BASH_PATH env	鈿狅笍 partially	Only works if Git Bash is in an exact path; doesn't fix stdin TTY bug fundamentally
PowerShell hook	鈿狅笍 partially	Works for some hook events but has its own stdin quirks (#46601)
Node.js (this template)	鉁?	Works uniformly; Node is already required for Claude Code

Background

Extracted from a real multi-machine workflow running Claude Code on both Linux and Windows. The Linux side worked out of the box with bash; the Windows side required this Node.js rewrite to handle the hook stdin / path quirks cleanly.

License

MIT 鈥?use freely, modify, redistribute.

Contributing

Found another Windows hook quirk not handled here? Open an issue or PR.

Author

@yvoolab