The questions engineers actually ask.

An HTTP endpoint your agent calls instead of the MCP server directly. The guard evaluates the call and either forwards it, holds it for a human, or refuses it. If the guard cannot evaluate a call it returns 503 and the call does not execute.

On the hosted tier, yes: the call and the policy context go to the judge to produce a decision. On the BYOK tier your judge key is used and only you hold it. On the self-hosted tier nothing leaves your network at all.

Fail behaviour is explicit: an unevaluable call is a 503, never a silent pass. Rate limits and the spend cap return 429. If a decision is wrong you can see exactly which rule or signal produced it in the decision record.

As rules, in a small deterministic language, per tool and per argument pattern. They compile into policy you can version and review. The judge never invents policy at runtime.

Yes. Self-hosted runs the same container image with a signed license, in your own VPC, with your own database. Talk to us for a license and deployment notes.

Per decision, per calendar month. The relay counts each evaluation once, reported decisions count once each, and retries never double-count. Overages bill at the plan rate against a spend cap you control.