mastyf.ai
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Download Mastyf Shield

A desktop app that sits between your local agents and their tools. Every tool call Claude Desktop, Cursor or Windsurf makes is checked against your policy before it runs.

Version
0.2.2
Platforms
macOS, Windows, Linux
Decision
Under 4.8 µs, on device

Mastyf Shield 0.2.2 for macOS

Apple Silicon (M1–M4) and Intel

Download for Apple Silicon (.dmg)Intel Mac (.dmg)

macOS 12 Monterey or newer. Works with Claude Desktop, Cursor, and Windsurf.

Optional here. Shield asks for it on first launch, then works offline for 14 days between checks.

No key yet? Get Developer Pro, $49/month
SHA-256, Apple Silicon9a48d91c89f02c91a0f837eb5f0821d3f94a81e9b2071d02c46f8812c9b10492

Set up in three steps

  1. 1Get a license keySubscribe to Developer Pro ($49/month) on Lemon Squeezy. The key arrives by email.
  2. 2InstallmacOS: drag the .dmg to Applications. Windows: run the .exe. Linux: run the .AppImage or install the .deb.
  3. 3ActivatePaste the key into the first-launch window. Shield starts checking MCP tool calls right away.

Requirements

macOS12 Monterey or newer. Universal build for Apple Silicon (arm64) and Intel (x86_64).
WindowsWindows 10 (build 19041+) or Windows 11, x64 or ARM64.
Linuxglibc 2.28+: Ubuntu 20.04+, Debian 11+, Fedora 34+, Arch.
Works withClaude Desktop, Cursor, Windsurf, VS Code, and any Model Context Protocol client.

Other ways to run Mastyf