Immortal Gate.
Permission before execution.
A gate is the explicit decision checkpoint between an agent proposal and a consequential external action.
The contract
The agent does not simply call the external tool. It first submits the proposed action and relevant context to the trust layer. The gate returns an explicit decision such as PASS, WARN, ESCALATE or BLOCK, plus evidence and reasons.
Where to place a gate
Before sending external email or messages.
Before publishing marketing or public content.
Before deployment or configuration changes.
Before purchases, refunds or other money-moving actions.
Before high-impact data writes or destructive operations.
Live foundation
The broader Gate product is the control-layer direction. NexusEval already exposes live evaluation/gate primitives such as POST /api/gate and launch-preflight routes that demonstrate the underlying machine-readable decision pattern.