Markitect boundary and reuse tests

docs/markitect-tool-reuse-boundary.md

@@ -8,6 +8,25 @@ This note records what `kontextual-engine` should reuse from
 `markitect-tool` instead of reimplementing. `markitect-tool` is the syntax
 layer; `kontextual-engine` is the system/runtime layer.
 
+## Dependency Contract
+
+`kontextual-engine` should integrate `markitect-tool` through documented public
+Python APIs and adapter modules. The preferred import surface is the
+top-level `markitect_tool` package or documented subpackages such as
+`markitect_tool.query`, `markitect_tool.ops`, `markitect_tool.memory`,
+`markitect_tool.policy`, and `markitect_tool.backend`.
+
+The engine must treat returned Markitect objects as adapter payloads. Domain
+state should persist serializable envelopes, source references, digests,
+lineage, policy decisions, and audit events rather than storing Markitect
+runtime objects as canonical engine entities.
+
+Required integration behavior is captured in
+`docs/markitect-tool-integration-usecases.md` and exercised by
+`tests/test_markitect_tool_contract.py`. These tests are allowed to skip when
+the optional `markitect-tool` dependency is not installed, but they become
+stability checks for the boundary when the `markdown` extra is installed.
+
 ## Reuse As Adapter Dependencies
 
 | Need in kontextual-engine | markitect-tool owner | Reuse posture |
@@ -22,6 +41,21 @@ layer; `kontextual-engine` is the system/runtime layer.
 | Document functions, templates, and generation hooks | `markitect_tool.document_function`, `markitect_tool.generation` | Invoke as syntax-layer processors. Keep provider calls behind `llm-connect`. |
 | Local label policy and policy adapter protocols | `markitect_tool.policy.*` | Reuse for markdown source/package filtering. Engine should expose policy-aware operations at artifact/service level. |
 
+## Adapter Ownership Rules
+
+- Markdown ingestion adapters may call `parse_markdown`, `parse_markdown_file`,
+  `query_document`, `extract_document`, and `snapshot_identity_for_file`.
+- Markdown transformation adapters may call `transform_markdown`,
+  `compose_files`, `resolve_includes`, Markitect contract checks, document
+  functions, templates, and workflow helpers.
+- Agent/context adapters may call Markitect context-package and local policy
+  APIs for markdown-backed context packages.
+- Engine domain code must not import Markitect APIs directly.
+- Service APIs must not expose the `mkt` CLI as the engine control surface.
+- Cross-format query, policy, audit, workflow run, versioning, and export
+  contracts remain engine-owned even when Markitect produced the markdown
+  payload.
+
 ## Do Not Reimplement Here
 
 - Markdown ASTs, section trees, frontmatter parsing, explode/implode, document
@@ -44,4 +78,3 @@ layer; `kontextual-engine` is the system/runtime layer.
 - Agent-operable context continuity and service/programmatic APIs.
 - Adapter registry that can call `markitect-tool`, `llm-connect`, and storage
   backends without embedding their internals.
-