diff --git a/docs/memory-graph-runtime.md b/docs/memory-graph-runtime.md
index 10f7d51..d1dd451 100644
--- a/docs/memory-graph-runtime.md
+++ b/docs/memory-graph-runtime.md
@@ -46,6 +46,10 @@ with `markitect-tool`.
 - `MemoryRuntimeService.export_runtime_envelope()` emits a portable runtime
   envelope containing graph nodes, edges, memory events, and audit traces with
   operation id, actor, policy decision, and filter metadata.
+- `MemoryRuntimeAdapterCapability`, `MemorySemanticIndex`,
+  `MemoryAuditPublisher`, and `MemoryRuntimeRegistry` define optional adapter
+  boundaries for vector/semantic indexes, durable audit sinks, remote registries,
+  and sibling memory runtimes.
 
 ## Boundary
 
@@ -64,5 +68,24 @@ with `markitect-tool`.
 - retention, refresh, compaction, review gates, and audit behavior
 - agent-safe update plans and Markitect-compatible export envelopes
 
+## External Adapter Boundaries
+
+External graph databases should implement `MemoryGraphRepository`; they are
+storage adapters, not alternate memory domain models. Enterprise policy systems
+should implement `PolicyGateway`; policy decisions remain explicit inputs to
+runtime operations.
+
+Optional advanced adapters use small dedicated ports:
+
+- `MemorySemanticIndex` for vector or hybrid retrieval indexes.
+- `MemoryAuditPublisher` for durable event sinks, webhooks, or SIEM pipelines.
+- `MemoryRuntimeRegistry` for remote memory registries and sibling runtimes
+  such as future phase-memory services.
+
+Adapters advertise `MemoryRuntimeAdapterCapability` with adapter kind,
+supported operations, optional dependencies, and whether they are deterministic
+local adapters. Adapter payloads must be serializable dictionaries or core
+runtime records, so core tests can stay deterministic and dependency-free.
+
 `infospace-bench` should consume these records and Markitect fixtures to measure
 retrieval quality, latency, budget pressure, and regression behavior.
diff --git a/src/kontextual_engine/__init__.py b/src/kontextual_engine/__init__.py
index 7ce2fea..cfeb146 100644
--- a/src/kontextual_engine/__init__.py
+++ b/src/kontextual_engine/__init__.py
@@ -116,7 +116,11 @@ from .ports import (
     BlobWriteResult,
     DirectorySourceConnector,
     FormatExtractor,
+    MemoryAuditPublisher,
     MemoryGraphRepository,
+    MemoryRuntimeAdapterCapability,
+    MemoryRuntimeRegistry,
+    MemorySemanticIndex,
     PolicyGateway,
     SourceConnector,
 )
@@ -271,6 +275,7 @@ __all__ = [
     "MetadataSchemaAssignment",
     "MetadataValidationIssue",
     "MetadataValueType",
+    "MemoryAuditPublisher",
     "MemoryCompactionRequest",
     "MemoryEdgeRecord",
     "MemoryEventRecord",
@@ -292,7 +297,10 @@ __all__ = [
     "MemoryRetentionRequest",
     "MemoryRuntimeExportRequest",
     "MemoryRuntimeExportResult",
+    "MemoryRuntimeAdapterCapability",
+    "MemoryRuntimeRegistry",
     "MemoryRuntimeService",
+    "MemorySemanticIndex",
     "MemorySourceSpan",
     "MemoryUpdatePlan",
     "MemoryUpdateRequest",
diff --git a/src/kontextual_engine/ports/__init__.py b/src/kontextual_engine/ports/__init__.py
index 0013e66..bcfe9e8 100644
--- a/src/kontextual_engine/ports/__init__.py
+++ b/src/kontextual_engine/ports/__init__.py
@@ -9,7 +9,13 @@ from .blob_storage import (
     digest_storage_key,
 )
 from .ingestion import DirectorySourceConnector, FormatExtractor, SourceConnector
-from .memory import MemoryGraphRepository
+from .memory import (
+    MemoryAuditPublisher,
+    MemoryGraphRepository,
+    MemoryRuntimeAdapterCapability,
+    MemoryRuntimeRegistry,
+    MemorySemanticIndex,
+)
 from .policy import AllowAllPolicyGateway, PolicyGateway
 from .repositories import AssetRegistryRepository
 
@@ -24,7 +30,11 @@ __all__ = [
     "digest_storage_key",
     "DirectorySourceConnector",
     "FormatExtractor",
+    "MemoryAuditPublisher",
     "MemoryGraphRepository",
+    "MemoryRuntimeAdapterCapability",
+    "MemoryRuntimeRegistry",
+    "MemorySemanticIndex",
     "PolicyGateway",
     "SourceConnector",
 ]
diff --git a/src/kontextual_engine/ports/memory.py b/src/kontextual_engine/ports/memory.py
index 3292eb0..ef995ee 100644
--- a/src/kontextual_engine/ports/memory.py
+++ b/src/kontextual_engine/ports/memory.py
@@ -2,7 +2,8 @@
 
 from __future__ import annotations
 
-from typing import Protocol
+from dataclasses import dataclass, field
+from typing import Any, Protocol
 
 from kontextual_engine.core import (
     AuditEvent,
@@ -14,6 +15,30 @@ from kontextual_engine.core import (
 )
 
 
+@dataclass(frozen=True)
+class MemoryRuntimeAdapterCapability:
+    adapter_name: str
+    adapter_kind: str
+    supported_operations: tuple[str, ...] = ()
+    required_dependencies: tuple[str, ...] = ()
+    deterministic_local: bool = False
+    metadata: dict[str, Any] = field(default_factory=dict)
+
+    def __post_init__(self) -> None:
+        object.__setattr__(self, "supported_operations", tuple(self.supported_operations))
+        object.__setattr__(self, "required_dependencies", tuple(self.required_dependencies))
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "adapter_name": self.adapter_name,
+            "adapter_kind": self.adapter_kind,
+            "supported_operations": list(self.supported_operations),
+            "required_dependencies": list(self.required_dependencies),
+            "deterministic_local": self.deterministic_local,
+            "metadata": dict(self.metadata),
+        }
+
+
 class MemoryGraphRepository(Protocol):
     def save_memory_profile(self, profile: MemoryProfileRecord) -> MemoryProfileRecord: ...
     def get_memory_profile(self, profile_id: str) -> MemoryProfileRecord: ...
@@ -56,3 +81,38 @@ class MemoryGraphRepository(Protocol):
         correlation_id: str | None = None,
         operation: str | None = None,
     ) -> list[AuditEvent]: ...
+
+
+class MemorySemanticIndex(Protocol):
+    name: str
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability: ...
+
+    def upsert_memory_nodes(self, nodes: list[MemoryNodeRecord]) -> dict[str, Any]: ...
+
+    def query_memory_nodes(
+        self,
+        *,
+        graph_id: str,
+        query: str,
+        limit: int = 10,
+        filters: dict[str, Any] | None = None,
+    ) -> list[dict[str, Any]]: ...
+
+
+class MemoryAuditPublisher(Protocol):
+    name: str
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability: ...
+
+    def publish_memory_audit_event(self, event: AuditEvent) -> dict[str, Any]: ...
+
+
+class MemoryRuntimeRegistry(Protocol):
+    name: str
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability: ...
+
+    def publish_runtime_envelope(self, envelope: dict[str, Any]) -> dict[str, Any]: ...
+
+    def fetch_runtime_envelope(self, reference: str) -> dict[str, Any]: ...
diff --git a/tests/test_memory_runtime_adapter_boundaries.py b/tests/test_memory_runtime_adapter_boundaries.py
new file mode 100644
index 0000000..44b4cf7
--- /dev/null
+++ b/tests/test_memory_runtime_adapter_boundaries.py
@@ -0,0 +1,140 @@
+from kontextual_engine import (
+    Actor,
+    ActorType,
+    AuditEvent,
+    AuditOutcome,
+    MemoryAuditPublisher,
+    MemoryRuntimeAdapterCapability,
+    MemoryRuntimeRegistry,
+    MemorySemanticIndex,
+    OperationContext,
+)
+
+
+def test_memory_runtime_adapter_capability_serializes_dependency_boundary() -> None:
+    capability = MemoryRuntimeAdapterCapability(
+        adapter_name="local-semantic-index",
+        adapter_kind="semantic_index",
+        supported_operations=("upsert_memory_nodes", "query_memory_nodes"),
+        required_dependencies=("numpy",),
+        deterministic_local=True,
+        metadata={"ownership": "optional-adapter"},
+    )
+
+    assert capability.to_dict() == {
+        "adapter_name": "local-semantic-index",
+        "adapter_kind": "semantic_index",
+        "supported_operations": ["upsert_memory_nodes", "query_memory_nodes"],
+        "required_dependencies": ["numpy"],
+        "deterministic_local": True,
+        "metadata": {"ownership": "optional-adapter"},
+    }
+
+
+def test_optional_memory_adapter_ports_exchange_serializable_payloads() -> None:
+    semantic_index: MemorySemanticIndex = FakeSemanticIndex()
+    audit_publisher: MemoryAuditPublisher = CapturingAuditPublisher()
+    registry: MemoryRuntimeRegistry = InMemoryRuntimeRegistry()
+    context = OperationContext.create(
+        Actor.create(ActorType.AI_AGENT, actor_id="agent-adapter-test"),
+        correlation_id="corr-adapter-boundary",
+    )
+    audit_event = AuditEvent.from_context(
+        "memory.runtime.export",
+        "memory-graph:memgraph-test",
+        AuditOutcome.SUCCESS,
+        context,
+        details={"operation_id": "memexport-test"},
+    )
+
+    upsert_result = semantic_index.upsert_memory_nodes([])
+    query_result = semantic_index.query_memory_nodes(graph_id="memgraph-test", query="contract boundary")
+    audit_result = audit_publisher.publish_memory_audit_event(audit_event)
+    registry_result = registry.publish_runtime_envelope(
+        {
+            "schema_version": "kontextual.memory.runtime-export.v1",
+            "graph_id": "memgraph-test",
+            "nodes": [],
+            "audit_events": [audit_event.to_dict()],
+        }
+    )
+    fetched = registry.fetch_runtime_envelope(registry_result["reference"])
+
+    assert semantic_index.capabilities().adapter_kind == "semantic_index"
+    assert upsert_result == {"upserted": 0}
+    assert query_result[0]["graph_id"] == "memgraph-test"
+    assert audit_result["event_id"] == audit_event.event_id
+    assert registry_result["reference"] == "memory-registry://memgraph-test"
+    assert fetched["audit_events"][0]["operation"] == "memory.runtime.export"
+
+
+class FakeSemanticIndex:
+    name = "fake-semantic-index"
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability:
+        return MemoryRuntimeAdapterCapability(
+            adapter_name=self.name,
+            adapter_kind="semantic_index",
+            supported_operations=("upsert_memory_nodes", "query_memory_nodes"),
+            deterministic_local=True,
+        )
+
+    def upsert_memory_nodes(self, nodes: list) -> dict:
+        return {"upserted": len(nodes)}
+
+    def query_memory_nodes(
+        self,
+        *,
+        graph_id: str,
+        query: str,
+        limit: int = 10,
+        filters: dict | None = None,
+    ) -> list[dict]:
+        return [
+            {
+                "graph_id": graph_id,
+                "node_id": "memnode-test",
+                "score": 1.0,
+                "query": query,
+                "filters": filters or {},
+                "limit": limit,
+            }
+        ]
+
+
+class CapturingAuditPublisher:
+    name = "capturing-audit-publisher"
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability:
+        return MemoryRuntimeAdapterCapability(
+            adapter_name=self.name,
+            adapter_kind="audit_sink",
+            supported_operations=("publish_memory_audit_event",),
+            deterministic_local=True,
+        )
+
+    def publish_memory_audit_event(self, event: AuditEvent) -> dict:
+        return {"published": True, "event_id": event.event_id, "operation": event.operation}
+
+
+class InMemoryRuntimeRegistry:
+    name = "in-memory-runtime-registry"
+
+    def __init__(self) -> None:
+        self.envelopes: dict[str, dict] = {}
+
+    def capabilities(self) -> MemoryRuntimeAdapterCapability:
+        return MemoryRuntimeAdapterCapability(
+            adapter_name=self.name,
+            adapter_kind="runtime_registry",
+            supported_operations=("publish_runtime_envelope", "fetch_runtime_envelope"),
+            deterministic_local=True,
+        )
+
+    def publish_runtime_envelope(self, envelope: dict) -> dict:
+        reference = f"memory-registry://{envelope['graph_id']}"
+        self.envelopes[reference] = dict(envelope)
+        return {"reference": reference, "graph_id": envelope["graph_id"]}
+
+    def fetch_runtime_envelope(self, reference: str) -> dict:
+        return self.envelopes[reference]
diff --git a/workplans/KONT-WP-0017-agentic-memory-graph-runtime.md b/workplans/KONT-WP-0017-agentic-memory-graph-runtime.md
index 0a0df7c..62bdc90 100644
--- a/workplans/KONT-WP-0017-agentic-memory-graph-runtime.md
+++ b/workplans/KONT-WP-0017-agentic-memory-graph-runtime.md
@@ -4,7 +4,7 @@ type: workplan
 title: "Agentic Memory Graph Runtime And Operational State"
 domain: markitect
 repo: kontextual-engine
-status: active
+status: completed
 owner: codex
 topic_slug: markitect
 planning_priority: medium
@@ -104,6 +104,11 @@ and operation. Runtime export envelopes include graph nodes, edges, memory
 events, audit traces, operation id, actor metadata, policy decisions, and
 filter metadata for portable inspection or handoff.
 
+The external adapter boundary slice is implemented. Optional semantic indexes,
+audit sinks, and runtime registries are defined as ports with capability
+metadata, while graph databases continue to implement `MemoryGraphRepository`
+and enterprise policy systems continue to implement `PolicyGateway`.
+
 ## P17.1 - Import and map Markitect memory contracts
 
 ```task
@@ -242,7 +247,7 @@ Output: audit model, observability events, export fixtures, and tests.
 
 ```task
 id: KONT-WP-0017-T007
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "c3cf79d8-389c-4583-a02d-303d0ce75cc1"
 ```