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THREAT

Permission Drift

agent scope expansionimplicit authorizationincremental boundary erosion

Permission drift is the gradual expansion of an agent's effective operational scope beyond its initial authorization — caused by the model inferring implicit permissions from context or user feedback.

ADVERSARIAL MECHANICS

A user says 'go ahead' after a read-only task. The agent, reasoning over history, infers that general authority has been granted. Each small inference creates a precedent that widens scope further until it exceeds the original authorization.

PROTOCOL CONTEXT (VEX AUTHORITY + MCP)

MCP's tool registry does not natively enforce session-scoped authorization. An agent connected to a registry may access any registered tool unless external enforcement is applied via authority policies.

ProvnAI Mitigation

ProvnAI combats drift through explicit policy boundaries and continuous behavioral drift detection in McpVanguard, which can flag incremental expansions against the original declared scope.