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PROTO

Execution Boundary

agent containmentscope enforcementVEX execution model

An execution boundary is a formally defined perimeter around an agent's authorized action space — specifying tools, data categories, network destinations, and filesystem paths.

BOUNDARY VIOLATION VECTORS

Boundaries are violated through Prompt Injection, SSRF, Path Traversal, and Permission Drift. Execution boundaries are declared at session initialization and enforced by the deterministic proxy throughout the lifecycle.

PROTOCOL CONTEXT (VEX — EXECUTION BOUNDARY MODEL)

The VEX Protocol's Boundary is declared as a structured policy within the Evidence Capsule Authority section. It specifies allowlists (not denylists) across Tool Scope, Data, Network, and Filesystem.

ProvnAI Mitigation

McpVanguard evaluates every tool call against the active boundary policy before forwarding. Because policy is embedded in the signed Evidence Capsule, it cannot be modified by in-session instructions.