Markitect boundary and reuse tests

docs/architecture-blueprint.md

@@ -201,8 +201,11 @@ Required MVP ports:
 
 Adapter rules:
 
-- `markitect-tool` is an adapter for markdown syntax and context-package
-  interoperability.
+- `markitect-tool` is an adapter for markdown syntax, selector extraction,
+  deterministic markdown operations, snapshot identity, contracts/runtime
+  checks, and context-package interoperability. Engine domain code must not
+  import it directly; adapter code should persist serializable Markitect
+  outputs as adapter provenance or representation metadata.
 - `llm-connect` or equivalent is an adapter for LLM providers.
 - `phase-memory` is an adjacent memory runtime; this engine may exchange opaque
   memory references or context packages but should not implement memory phases.