feat(api): add GET /knowledge/graph endpoint for full graph visualization

Returns all entities and resolved relations in a flat node/edge format
optimized for graph rendering. Replaces the frontend's use of the
recent memory endpoint which only returned a subset of relations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/api/v2/routers/knowledge_router.py

@@ -20,6 +20,7 @@
     ProjectConfigV2ExternalDep,
     AppConfigDep,
     EntityRepositoryV2ExternalDep,
+    RelationRepositoryV2ExternalDep,
     ProjectExternalIdPathDep,
     TaskSchedulerDep,
     FileServiceV2ExternalDep,
@@ -31,6 +32,9 @@
     EntityResolveRequest,
     EntityResolveResponse,
     EntityResponseV2,
+    GraphEdge,
+    GraphNode,
+    GraphResponse,
     MoveEntityRequestV2,
     MoveDirectoryRequestV2,
     DeleteDirectoryRequestV2,
@@ -56,6 +60,50 @@ def _schedule_vector_sync_if_enabled(
         )
 
 
+## Graph endpoint
+
+
+@router.get("/graph", response_model=GraphResponse)
+async def get_graph(
+    project_id: ProjectExternalIdPathDep,
+    entity_repository: EntityRepositoryV2ExternalDep,
+    relation_repository: RelationRepositoryV2ExternalDep,
+) -> GraphResponse:
+    """Return all entities and resolved relations for knowledge graph visualization.
+
+    Returns a flat node/edge structure optimized for rendering with graph libraries.
+    Only includes resolved relations (where to_id is not null).
+    """
+    logger.info("API v2 request: get_graph")
+
+    # Fetch all entities for this project
+    entities = await entity_repository.find_all(use_load_options=False)
+    nodes = [
+        GraphNode(
+            external_id=entity.external_id,
+            title=entity.title,
+            note_type=entity.note_type,
+            file_path=entity.file_path,
+        )
+        for entity in entities
+    ]
+
+    # Fetch all resolved relations (to_id is not null) with eager-loaded entities
+    relations = await relation_repository.find_all()
+    edges = [
+        GraphEdge(
+            from_id=relation.from_entity.external_id,
+            to_id=relation.to_entity.external_id,
+            relation_type=relation.relation_type,
+        )
+        for relation in relations
+        if relation.to_entity is not None
+    ]
+
+    logger.info(f"API v2 response: graph with {len(nodes)} nodes and {len(edges)} edges")
+    return GraphResponse(nodes=nodes, edges=edges)
+
+
 ## Resolution endpoint
 
 

src/basic_memory/schemas/v2/__init__.py

@@ -10,6 +10,11 @@
     ProjectResolveRequest,
     ProjectResolveResponse,
 )
+from basic_memory.schemas.v2.graph import (
+    GraphEdge,
+    GraphNode,
+    GraphResponse,
+)
 from basic_memory.schemas.v2.resource import (
     CreateResourceRequest,
     UpdateResourceRequest,
@@ -25,6 +30,9 @@
     "DeleteDirectoryRequestV2",
     "ProjectResolveRequest",
     "ProjectResolveResponse",
+    "GraphEdge",
+    "GraphNode",
+    "GraphResponse",
     "CreateResourceRequest",
     "UpdateResourceRequest",
     "ResourceResponse",

src/basic_memory/schemas/v2/graph.py

@@ -0,0 +1,31 @@
+"""Graph visualization schemas for the knowledge graph endpoint."""
+
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class GraphNode(BaseModel):
+    """A node in the knowledge graph visualization."""
+
+    external_id: str = Field(..., description="Entity external ID (UUID)")
+    title: str = Field(..., description="Entity title")
+    note_type: Optional[str] = Field(None, description="Note type (e.g., note, spec, task)")
+    file_path: str = Field(..., description="Relative file path")
+
+
+class GraphEdge(BaseModel):
+    """An edge in the knowledge graph visualization."""
+
+    from_id: str = Field(..., description="External ID of source entity")
+    to_id: str = Field(..., description="External ID of target entity")
+    relation_type: str = Field(..., description="Type of relation")
+
+
+class GraphResponse(BaseModel):
+    """Complete knowledge graph for visualization."""
+
+    nodes: list[GraphNode] = Field(default_factory=list, description="All entities as nodes")
+    edges: list[GraphEdge] = Field(
+        default_factory=list, description="All resolved relations as edges"
+    )