Core documentation

22. Define a conforming host role and ship the Open Engine host as a reference implementation

adr: 22
title: Define a conforming host role and ship the Open Engine host as a reference implementation
status: accepted
date: 2026-06-22

§Context

ASP needs a coordinator that owns policy, freshness, assessment aggregation, decisions, and mediated apply. That coordinator does not have to be a centralized Open Engine runtime. It can be embedded in an editor, harness, CI system, or another vendor implementation.

§Decision

ASP requires a conforming host role, not a mandatory centralized host implementation.

The Open Engine may build @the-open-engine/asp as the private reference/default host implementation. It must pass the same conformance suite expected of any other host and must not gain privileged Lattice-specific behavior.

§Consequences

• Docs must say “a conforming ASP host” when describing the standard.
• Docs may say “@the-open-engine/asp reference host” when describing our implementation path.
• ASP servers must be testable against fake and independent hosts, not only the Open Engine host.
• Harnesses may embed a host or invoke the reference host.
• ACE is one optional harness/client. ACE may consume a configured conforming host through an adapter, but it does not own ASP host distribution, host startup policy, provider authority, Lattice provisioning, or ASP release gating.