Runtime Boundaries

Current implementation evidence: docs/runtime-capabilities.html,

docs/local-effects-runtime.html, docs/fetch-browser-runtime.html,

docs/web-runtime.html, and docs/service-boundary-runtime.html.

Boundary Model

0x0 source capability annotations are not the same thing as host runtime

implementations. Runtime docs define how app code reaches host effects.

Current Runtime Areas

The current docs cover:

• local filesystem, CLI, environment, and subprocess boundary;
• HTTP client and browser snapshot boundary;
• HTTP server, routing, WebSocket, and LiveView-compatible app boundary;
• database, auth/OIDC, object-store, search, email, observability, backup,

restore, and job boundary;

• production host and fake adapter distinction.

Fake Adapters

Fake adapters exist for deterministic tests. A fake adapter must not be the only

passing path for a production feature claim.

Practical Rule

When a page describes runtime behavior, it must say whether the behavior is:

• core language behavior;
• production host runtime behavior;
• app-specific runtime behavior;
• fake test adapter behavior;
• planned or deferred.