Constable implements ZTG-3 on Zero Trust Governance as an effect-surface registry plus a dispatch architecture in which the registered surfaces are the only reachable path from the agent to the world.
No ambient effect authority. Constable's agent runtime holds no general-purpose capability to act on external systems. Every outbound effect is dispatched through a registered surface adaptor; there is no reachable code path by which the agent can produce an external effect except by routing a proposal through the gate to a registered surface. Effect capability is held by the surface mechanism, not ambiently by the agent.
Surface registry. Surfaces and sub-surfaces are registered with their declared
harm-class default, compositional multiplier, and reversal_strategy. Sub-surface
declarations are validated to tighten, never relax, their parent's defaults. The
registry is carried in the ZTG-0e on Zero Trust Governance governance bundle, so registration and
declaration changes are signed by a ratifying principal, recorded, ordered, and
applied atomically; the gate evaluates against the registry version pinned at
decision-time.
Routing and provenance. When the gate authorizes an action, Constable routes it
to the matching registered surface and records SURFACE_ROUTE_SELECTED, binding the
surface's harm class, multiplier, and reversal strategy into the action's provenance
alongside the ZTG-5 on Zero Trust Governance fields. Reversal strategy is recorded as provenance only; the
gate selection follows harm class and computed assessment per ZTG-5 on Zero Trust Governance and is never
discounted by the presence of a reversal strategy.
Closure verification. Constable treats the absence of reachable unregistered effect paths as a verifiable architectural property and tests for it (below). A reachable effect path discovered without a corresponding registered surface is raised as an integrity violation and triggers Stasis (ZTG-2 on Zero Trust Governance) rather than being auto-registered.
Conformance tests. Constable's internal testing for ZTG-3 on Zero Trust Governance includes: reachability analysis confirming no agent-reachable effect path bypasses a registered surface; ambient-authority tests confirming the agent holds no general-purpose effect capability; declaration tests confirming sub-surfaces tighten and never relax defaults; provenance tests confirming reversal strategy is recorded but never relaxes gate or harm class; routing tests confirming every effect records its surface selection; registry-governance tests confirming registration changes are ZTG-0e on Zero Trust Governance transitions; and breach tests confirming a reachable unregistered channel triggers Stasis. The protocol is documented in the conformance verification specification referenced in §22.