Ladybug Graph Store API¶

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API reference for amplihack.memory.ladybug_store.KuzuGraphStore.

Import¶

# Preferred — stable package-level export
from amplihack.memory import KuzuGraphStore

# Direct module import
from amplihack.memory.ladybug_store import KuzuGraphStore

Constructor¶

KuzuGraphStore(
    db_path: str | Path | None = None,
    buffer_pool_size: int = 67_108_864,   # 64 MB
    max_db_size: int = 1_073_741_824,     # 1 GB
    read_only: bool = False,
)

When db_path is not None, a sidecar <db_path>.lock file is created and locked via fcntl.flock before the database is opened. Read-only mode uses LOCK_SH; write mode uses LOCK_EX. The lock is released by close().

Schema Methods¶

ensure_table¶

store.ensure_table(table: str, schema: dict[str, str]) -> None

Create a node table if it doesn't exist. The schema maps column names to Kùzu types. If node_id is included in the schema, it becomes the PRIMARY KEY. You must include node_id for create_node / get_node to work.

store.ensure_table("Session", {
    "node_id": "STRING",
    "start_time": "STRING",
    "status": "STRING",
    "context": "STRING",
})

ensure_rel_table¶

store.ensure_rel_table(
    rel_type: str,
    from_table: str,
    to_table: str,
    schema: dict[str, str] | None = None,
) -> None

Create a relationship table if it doesn't exist.

store.ensure_rel_table("REMEMBERS", "Session", "EpisodicMemory", schema={
    "strength": "DOUBLE",
})

Node CRUD¶

create_node¶

store.create_node(table: str, properties: dict[str, Any]) -> str

Create a node with the given properties. Returns the node_id (auto-generated UUID if not provided in properties).

node_id = store.create_node("Session", {
    "start_time": "2026-04-10T07:00:00Z",
    "status": "active",
})

get_node¶

store.get_node(table: str, node_id: str) -> dict[str, Any] | None

Retrieve a node by ID. Returns None if not found.

update_node¶

store.update_node(table: str, node_id: str, properties: dict[str, Any]) -> None

Update specific properties on an existing node. Only the provided keys are modified.

delete_node¶

store.delete_node(table: str, node_id: str) -> None

Delete a node by ID.

Querying¶

query_nodes¶

store.query_nodes(
    table: str,
    filters: dict[str, Any] | None = None,
    limit: int = 100,
) -> list[dict[str, Any]]

Query nodes with optional equality filters. Returns up to limit rows.

sessions = store.query_nodes("Session", filters={"status": "active"}, limit=10)

search_nodes¶

store.search_nodes(
    table: str,
    text: str,
    fields: list[str] | None = None,
    limit: int = 20,
) -> list[dict[str, Any]]

Keyword-tokenized search. Splits text into up to 6 meaningful keywords (length ≥ 3, stop words removed), then matches any keyword against all STRING columns (or only the specified fields) using Cypher CONTAINS(). Falls back to exact substring match when no usable tokens remain.

results = store.search_nodes(
    "SemanticMemory",
    text="authentication",
    fields=["content", "concept"],
    limit=5,
)

Edge Operations¶

create_edge¶

store.create_edge(
    rel_type: str,
    from_table: str,
    from_id: str,
    to_table: str,
    to_id: str,
    properties: dict[str, Any] | None = None,
) -> None

Create a directed edge between two nodes.

store.create_edge(
    "REMEMBERS", "Session", session_id,
    "EpisodicMemory", memory_id,
    properties={"strength": 0.9},
)

get_edges¶

store.get_edges(
    node_id: str,
    rel_type: str | None = None,
    direction: str = "out",
) -> list[dict[str, Any]]

Query edges connected to a node. direction controls traversal: "out" (outgoing), "in" (incoming), or "both". Returns dicts with from_id, to_id, edge properties, and optionally rel_type.

delete_edge¶

store.delete_edge(rel_type: str, from_id: str, to_id: str) -> None

Delete a specific edge.

Import / Export¶

export_nodes¶

store.export_nodes(
    node_ids: list[str] | None = None,
) -> list[tuple[str, str, dict]]

Export nodes as (table, node_id, properties) tuples. If node_ids is None, exports all nodes.

export_edges¶

store.export_edges(
    node_ids: list[str] | None = None,
) -> list[tuple[str, str, str, str, str, dict]]

Export edges as (rel_type, from_table, from_id, to_table, to_id, properties) tuples. If node_ids is provided, exports edges where either endpoint is in the set.

import_nodes / import_edges¶

store.import_nodes(nodes: list[tuple[str, str, dict]]) -> int
store.import_edges(edges: list[tuple[str, str, str, str, str, dict]]) -> int

Import nodes and edges from the export format ((table, node_id, props) for nodes). Returns the count of items imported. Only imports into already-known tables. Duplicate node_id values are silently skipped (MERGE semantics).

Utility¶

get_all_node_ids¶

store.get_all_node_ids(table: str | None = None) -> set[str]

Return all node IDs across all tables, or for a specific table.

close¶

store.close() -> None

Close the database connection and release the flock. Always call this when done, or use a context manager pattern:

store = KuzuGraphStore(db_path="/tmp/test.db")
try:
    store.create_node("Session", {"status": "active"})
finally:
    store.close()

Concurrency¶

KuzuGraphStore is thread-safe within a single process (protected by threading.RLock). Cross-process safety is provided by fcntl.flock:

Process A: KuzuGraphStore(db_path="/data/graph")  → acquires LOCK_EX
Process B: KuzuGraphStore(db_path="/data/graph")  → blocks until A releases
Process C: KuzuGraphStore(db_path="/data/graph", read_only=True)
           → blocks until A releases (readers wait for writers)

Process D: KuzuGraphStore(db_path="/data/graph", read_only=True)  → acquires LOCK_SH
Process E: KuzuGraphStore(db_path="/data/graph", read_only=True)  → acquires LOCK_SH (concurrent)
Process F: KuzuGraphStore(db_path="/data/graph")  → blocks until D and E release

Lock timeout is 30 seconds. If the lock cannot be acquired, TimeoutError is raised.

Security¶

All identifiers (table names, relationship types, property keys) interpolated into Cypher queries are validated against ^[a-zA-Z_][a-zA-Z0-9_]*$. Invalid identifiers raise ValueError. User-supplied values always use $param binding, never string interpolation.

Related¶

• Ladybug Migration Guide
• Kuzu Memory Schema
• Kuzu Code Schema
• Memory README