Backend fabric extension

workplans/MKTT-WP-0006-cache-backend-architecture-core.md

@@ -3,7 +3,7 @@ id: MKTT-WP-0006
 type: workplan
 title: "Optional Cache Backend Architecture Core"
 domain: markitect
-status: todo
+status: done
 owner: markitect-tool
 topic_slug: markitect
 planning_priority: P1
@@ -51,7 +51,7 @@ make them awkward later.
 
 ```task
 id: MKTT-WP-0006-T001
-status: todo
+status: done
 priority: high
 state_hub_task_id: "8c04f146-942c-45b8-9a7b-3bd61916aa4b"
 ```
@@ -67,11 +67,15 @@ Define capability names, backend manifests, and compatibility checks for:
 - policy enforcement
 - provenance
 
+Implemented as `BACKEND_CAPABILITIES`, backend manifests, and compatibility
+checks in the optional `backend` package. Unknown extension capabilities are
+preserved as metadata while known capabilities remain stable for dispatch.
+
 ## P6.2 - Define snapshot model and content identity
 
 ```task
 id: MKTT-WP-0006-T002
-status: todo
+status: done
 priority: high
 state_hub_task_id: "5debc135-908a-47ed-ba15-564610970e38"
 ```
@@ -82,11 +86,15 @@ parser version, parse options, and contract version where relevant.
 Include a placeholder for stable content-unit identities and dependency edges so
 references/chunks can be cached and invalidated later.
 
+Implemented with `SnapshotIdentity`, `DocumentSnapshot`, `DependencyEdge`, and
+`snapshot_identity_for_file`, keyed by content hash, parser id/version, parse
+options hash, and optional contract hash.
+
 ## P6.3 - Define backend interfaces
 
 ```task
 id: MKTT-WP-0006-T003
-status: todo
+status: done
 priority: high
 state_hub_task_id: "a3e37112-1197-4f6f-8de8-7b3067ef060e"
 ```
@@ -97,11 +105,15 @@ context package registries, and access policy gateways.
 Leave room for processor-result stores, reference graph adapters, and source-map
 or provenance adapters.
 
+Implemented protocol interfaces for snapshot backends, index backends, query
+adapters, context package registries, access policy gateways, and processor
+result stores.
+
 ## P6.4 - Implement local backend registry
 
 ```task
 id: MKTT-WP-0006-T004
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "6c9b8765-4d14-436d-a2c9-c028a31aaade"
 ```
@@ -109,11 +121,15 @@ state_hub_task_id: "6c9b8765-4d14-436d-a2c9-c028a31aaade"
 Load backend manifests from project config and expose registered capabilities
 without importing optional dependencies unless needed.
 
+Implemented `BackendRegistry`, YAML/Markdown `markitect-backend` manifest
+loading, default local manifest paths, examples, and capability filtering
+without importing backend implementation dependencies.
+
 ## P6.5 - Add provenance envelope
 
 ```task
 id: MKTT-WP-0006-T005
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "7b551eae-99c8-4c8a-b781-18d59d318707"
 ```
@@ -121,11 +137,14 @@ state_hub_task_id: "7b551eae-99c8-4c8a-b781-18d59d318707"
 Add provenance metadata shared by snapshots, query results, context packages,
 and diagnostics.
 
+Implemented `ProvenanceEnvelope` with operation, snapshot, source, content hash,
+dependency edges, backend id, policy decision id, and extension metadata.
+
 ## P6.6 - Add CLI scaffolding
 
 ```task
 id: MKTT-WP-0006-T006
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "921e589c-8b0d-4eeb-8834-4a4c6c73da65"
 ```
@@ -140,6 +159,10 @@ mkt cache status
 
 No persistent write behavior is required in this task.
 
+Implemented read-only `mkt backend list`, `mkt backend inspect`, and
+`mkt backend snapshot-id`. The existing `mkt cache status` remains the
+lightweight file-manifest status command.
+
 ## Exit Criteria
 
 - Core CLI still works without any backend.