search_nodes
Find knowledge graph nodes by searching entity names, types, or observation content to retrieve relevant information from stored data.
Instructions
Search for nodes in the knowledge graph based on a query
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | The search query to match against entity names, types, and observation content |
Implementation Reference
- src/manager.ts:531-592 (handler)The core handler function for searching nodes using Fuse.js fuzzy search on entity names, types, and observations, then retrieving related relations from DuckDB.
async searchNodes(query: string): Promise<KnowledgeGraph> { if (!query || query.trim() === "") { return { entities: [], relations: [] }; } // Get all entities const allEntities = await this.getAllEntities(); // Update Fuse.js collection this.fuse.setCollection(allEntities); // Execute search const results = this.fuse.search(query); // Extract entities from search results (remove duplicates) const uniqueEntities = new Map<string, Entity>(); for (const result of results) { if (!uniqueEntities.has(result.item.name)) { uniqueEntities.set(result.item.name, result.item); } } const entities = Array.from(uniqueEntities.values()); // Create a set of entity names const entityNames = entities.map((entity) => entity.name); if (entityNames.length === 0) { return { entities: [], relations: [] }; } // Create placeholders const placeholders = entityNames.map(() => "?").join(","); using conn = await this.getConn(); // Get related relations 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, }; } - src/server.ts:159-181 (registration)Registers the 'search_nodes' tool with the MCP server, defining its name, description, input schema (query string), and handler that delegates to the manager.
server.tool( "search_nodes", "Search for nodes in the knowledge graph based on a query", { query: z .string() .describe( "The search query to match against entity names, types, and observation content" ), }, async ({ query }) => ({ content: [ { type: "text", text: JSON.stringify( await knowledgeGraphManager.searchNodes(query), null, 2 ), }, ], }) ); - src/types.ts:55-64 (schema)TypeScript interface defining the KnowledgeGraphManagerInterface, including the searchNodes method signature for type safety.
export type KnowledgeGraphManagerInterface = { createEntities(entities: Entity[]): Promise<Entity[]>; createRelations(relations: Relation[]): Promise<Relation[]>; addObservations(observations: Array<Observation>): Promise<Observation[]>; deleteEntities(entityNames: string[]): Promise<void>; deleteObservations(deletions: Array<Observation>): Promise<void>; deleteRelations(relations: Relation[]): Promise<void>; searchNodes(query: string): Promise<KnowledgeGraph>; openNodes(names: string[]): Promise<KnowledgeGraph>; }; - src/types.ts:47-50 (schema)Type definition for KnowledgeGraph, the return type of searchNodes.
export type KnowledgeGraph = { entities: Entity[]; relations: Relation[]; };