Your model proposes.Mastyf decides.

AI agents don't just answer questions. They take actions: reading files, changing code, calling APIs. Mastyf decides which of those actions actually happen.

An agent works in a loop. The model reads your request, chooses a tool, and that tool runs on your real systems: your files, your code, your data.

Without a boundary, whatever the model proposes runs. If untrusted content steers the model off course, an action outside your policy executes as easily as a safe one. And nothing records why.

With Mastyf in place, every tool call stops at the boundary first. It's checked against your policy: pattern rules, schema validation and an optional semantic review. Calls within policy pass straight through. Calls outside it are blocked before they ever reach the tool.

Mastyf sits outside the model's reasoning loop. It doesn't ask the model to police itself, and it doesn't depend on any one vendor. Working at the tool-call layer, one policy protects agents built on any model, in any client. Change your model or framework, and your policy stays the same.

Every decision is written to a tamper-evident audit log, so you can always show what your agent tried to do, and what was stopped.

Your model proposes. Mastyf decides.