# install-mfw

> Claude/Codex skill by [@semgrep](https://omgskills.com/library/semgrep/index.md) · 18 stars · Updated 2026-10-22

Install the mfw (Semgrep Malware Firewall) CLI via the curl|sh installer and walk the user through setup — trust store, PATH shims, shell integration, and the background daemon — asking questions at real decision points. Detects when the user's shell rc files are \*managed\* (symlinked into nix / home-manager / chezmoi / GNU stow / a dotfiles git repo) and, instead of clobbering them, adds mfw's source line to the right source-of-truth. Use when the user wants to install, set up, or onboard mfw on this machine.

## Install

```sh
git clone https://github.com/semgrep/guardian /tmp/guardian && ln -s /tmp/guardian/plugin/skills/install-mfw ~/.claude/skills/install-mfw
```

## From README

mfw and set up the mfw client — Semgrep's Malware Firewall, a local MITM proxy that gates package-manager downloads (pip / npm / pnpm / uv / cargo / maven / gem / nuget / composer / go) on Semgrep's backend before bytes hit disk. $ARGUMENTS may carry a backend/dist URL override (e.g. https://example.semgrep.dev) or --store system. Default backend is https://semgrep.dev (mfw is distributed off prod). If empty, use the defaults. Your job: drive the end to end, ask the user only at genuine decision points (via AskUserQuestion), and — the part that needs care — never edit a managed (symlinked) shell rc file in place. Work through the steps in order.

## Links

- HTML page: https://omgskills.com/library/semgrep/guardian/plugin/skills/install-mfw/
- GitHub: https://github.com/semgrep/guardian
- Author: [@semgrep](https://omgskills.com/library/semgrep/index.md)

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