What is cys?
cys is a Claude Code mod by koenvdheide that tracks the temporary files Claude creates and asks it to clean them up at the end of each turn. It is listed under Interface and has no public popularity data yet.
| Type | Claude code mod |
|---|---|
| Author | koenvdheide |
| Repository | koenvdheide/cys |
| Popularity | no public popularity data yet |
| Category | Interface |
| Security | Low risk (100/100) |
| Rank | #3,715 of 5,272 Claude Code mods; #1,545 in Interface |
| License | MIT |
| Last commit | 2026-10-16 |
| Hooks | 4 events |
| Sees | classic hooks, mcp__cys__register calls |
| Draws on | nothing |
Is cys safe to install?
cys scores 100/100 on the MCPMods security check: Low risk. No checks raised a concern. It passed 8 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 |
|---|---|
| No network access | Pass |
| Starts no processes | Pass |
| Writes no files or config | Pass |
| Doesn't read environment variables | Pass |
| Only sees the events it hooks | Pass |
| Doesn't drive Claude | Pass |
| Passes claude plugin validate | Pass |
| Has an open-source license | Pass |
API calls in its code
| Call | What it means |
|---|---|
$.fs.exists | reads files |
$.fs.stat | reads files |
$.session.cwd | |
$.session.id | |
$.store.delete | keeps its own state |
$.store.get | keeps its own state |
$.store.keys | keeps its own state |
$.store.set | keeps its own state |
$.tool.register | drives Claude |
How do I install cys?
- 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/koenvdheide/cys claude plugin validate ./cys/.
- Install it. Run this in your terminal, then /reload-plugins in an open session.
git clone https://github.com/koenvdheide/cys && claude --plugin-dir ./cys/.
Or ask Claude to set it up
Paste this into Claude Code and it installs cys for you:
Install the "cys" Claude Code mod from https://github.com/koenvdheide/cys. Run claude plugin validate on it first and show me what it can access before you enable it.