open_nodes
Retrieve specific knowledge graph entities by name to access stored information in DuckDB for conversation memory and data queries.
Instructions
Open specific nodes in the knowledge graph by their names
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| names | Yes | An array of entity names to retrieve |
Implementation Reference
- src/manager.ts:630-716 (handler)Implementation of the openNodes method in KnowledgeGraphManager. Retrieves entities by names using SQL queries, groups observations, fetches related relations, and returns a KnowledgeGraph.
async openNodes(names: string[]): Promise<KnowledgeGraph> { if (names.length === 0) { return { entities: [], relations: [] }; } try { using conn = await this.getConn(); // Create placeholders const placeholders = names.map(() => "?").join(","); // Retrieve entities and observations at once using LEFT JOIN const reader = await conn.executeAndReadAll( ` SELECT e.name, e.entityType, o.content FROM entities e LEFT JOIN observations o ON e.name = o.entityName WHERE e.name IN (${placeholders}) `, names ); const rows = reader.getRows(); // Group results by entity const entitiesMap = new Map<string, Entity>(); for (const row of rows) { const name = row[0] as string; const entityType = row[1] as string; const content = row[2] as string | null; if (!entitiesMap.has(name)) { // Create a new entity entitiesMap.set(name, { name, entityType, observations: content ? [content] : [], }); } else if (content) { // Add observation to existing entity entitiesMap.get(name)!.observations.push(content); } } const entities = Array.from(entitiesMap.values()); // Create a set of entity names const entityNames = entities.map((entity) => entity.name); // Get related relations if (entityNames.length > 0) { const placeholders = entityNames.map(() => "?").join(","); const relationsReader = await conn.executeAndReadAll( ` SELECT from_entity as "from", to_entity as "to", relationType FROM relations WHERE from_entity IN (${placeholders}) OR to_entity IN (${placeholders}) `, [...entityNames, ...entityNames] ); const relationsData = relationsReader.getRows(); // Convert results to an array of Relation objects const relations = relationsData.map((row: any) => { return { from: row[0] as string, to: row[1] as string, relationType: row[2] as string, }; }); return { entities, relations, }; } else { return { entities, relations: [], }; } } catch (error: unknown) { this.logger.error("Error opening nodes", extractError(error)); return { entities: [], relations: [] }; } } - src/server.ts:184-204 (registration)Registers the 'open_nodes' MCP tool with server.tool, defining input schema (array of strings for names) and delegating execution to knowledgeGraphManager.openNodes.
server.tool( "open_nodes", "Open specific nodes in the knowledge graph by their names", { names: z .array(z.string()) .describe("An array of entity names to retrieve"), }, async ({ names }) => ({ content: [ { type: "text", text: JSON.stringify( await knowledgeGraphManager.openNodes(names), null, 2 ), }, ], }) ); - src/types.ts:63-63 (schema)TypeScript interface definition for the openNodes method in KnowledgeGraphManager.
openNodes(names: string[]): Promise<KnowledgeGraph>;