What is katzensteg?
katzensteg is a Claude Code mod by rjwittams that game and HTML panels backed by the headless Katzensteg WM. Needs CLAUDE_CODE_ENABLE_FUNCTION_HOOKS=1. It is listed under Games and has 3 GitHub stars.
| Type | Claude code mod |
|---|---|
| Author | rjwittams |
| Repository | rjwittams/katzensteg |
| Popularity | 3 GitHub stars |
| Category | Games |
| Security | High risk (44/100) |
| Rank | #961 of 5,272 Claude Code mods; #25 in Games |
| Last commit | 2026-10-16 |
| Hooks | 8 events |
| Sees | ? calls, the system prompt |
| Draws on | AbovePrompt, Pane |
Is katzensteg safe to install?
katzensteg scores 44/100 on the MCPMods security check: High risk. Things to review: sends data over the network; starts processes outside the sandbox; writes files or config; reads environment variables. It passed 2 of 8 checks.
Mod footprints come from claude plugin validate, which lists every event a mod hooks and every API call it makes without running it.
| Check | Result |
|---|---|
| Sends data over the network | Review |
| Starts processes outside the sandbox | Review |
| Writes files or config | Review |
| Reads environment variables | Review |
| Only sees the events it hooks | Pass |
| Doesn't drive Claude | Pass |
| Validator reported problems | Note |
| No license detected | Note |
API calls in its code
| Call | What it means |
|---|---|
$.clock.after | |
$.clock.sleep | |
$.command.register | |
$.env.get | reads env vars |
$.env.set | sets env vars |
$.fs.exists | reads files |
$.fs.write | writes files |
$.http.fetch | network requests |
$.process.run | runs processes |
$.store.get | keeps its own state |
$.store.set | keeps its own state |
$.tool.register | drives Claude |
$.ui.blit | draws interface |
$.ui.close | draws interface |
$.ui.invalidate | draws interface |
$.ui.log | draws interface |
$.ui.open | draws interface |
$.ui.resolve | draws interface |
How do I install katzensteg?
- Check your Claude Code version. Mods need Claude Code 2.1.287 or later and are on by default.
claude --version
- Read its footprint. This lists every event it hooks and every API call it makes, without running it.
git clone https://github.com/rjwittams/katzensteg claude plugin validate ./katzensteg/tools/claude-code-plugin
- Install it. Run this in your terminal, then /reload-plugins in an open session.
git clone https://github.com/rjwittams/katzensteg && claude --plugin-dir ./katzensteg/tools/claude-code-plugin
Or ask Claude to set it up
Paste this into Claude Code and it installs katzensteg for you:
Install the "katzensteg" Claude Code mod from https://github.com/rjwittams/katzensteg/tree/main/tools/claude-code-plugin. Run claude plugin validate on it first and show me what it can access before you enable it.