memento-mcp

Instructions

Implementation Reference

• src/server/handlers/listToolsHandler.ts:446-460 (registration)

  Tool registration and schema definition for get_graph_at_time in the list of temporal tools
  { name: 'get_graph_at_time', description: 'Get your Memento MCP knowledge graph memory as it existed at a specific point in time', inputSchema: { type: 'object', properties: { timestamp: { type: 'number', description: 'The timestamp (in milliseconds since epoch) to query the graph at', }, }, required: ['timestamp'], }, },
• src/server/handlers/callToolHandler.ts:129-138 (handler)

  MCP tool handler switch case that executes get_graph_at_time by calling KnowledgeGraphManager.getGraphAtTime
  case 'get_graph_at_time': try { const graph = await knowledgeGraphManager.getGraphAtTime(args.timestamp); return { content: [{ type: 'text', text: JSON.stringify(graph, null, 2) }] }; } catch (error: Error | unknown) { const errorMessage = error instanceof Error ? error.message : String(error); return { content: [{ type: 'text', text: `Error retrieving graph at time: ${errorMessage}` }], }; }
• src/KnowledgeGraphManager.ts:1204-1210 (helper)

  KnowledgeGraphManager method that delegates getGraphAtTime to the storage provider
  async getGraphAtTime(timestamp: number): Promise<KnowledgeGraph> { if (!this.storageProvider || typeof this.storageProvider.getGraphAtTime !== 'function') { throw new Error('Storage provider does not support temporal graph operations'); } return this.storageProvider.getGraphAtTime(timestamp); }
• src/storage/neo4j/Neo4jStorageProvider.ts:1541-1597 (handler)

  Core implementation of getGraphAtTime in Neo4jStorageProvider using temporal queries on validFrom/validTo fields
  async getGraphAtTime(timestamp: number): Promise<KnowledgeGraph> { try { const startTime = Date.now(); // Query for entities valid at timestamp const entityQuery = ` MATCH (e:Entity) WHERE e.validFrom <= $timestamp AND (e.validTo IS NULL OR e.validTo > $timestamp) RETURN e `; // Execute entity query const entityResult = await this.connectionManager.executeQuery(entityQuery, { timestamp }); // Convert nodes to entities const entities = entityResult.records.map((record) => { const node = record.get('e').properties; return this.nodeToEntity(node); }); // Query for relations valid at timestamp const relationQuery = ` MATCH (from:Entity)-[r:RELATES_TO]->(to:Entity) WHERE r.validFrom <= $timestamp AND (r.validTo IS NULL OR r.validTo > $timestamp) RETURN r, from.name AS fromName, to.name AS toName `; // Execute relation query const relationResult = await this.connectionManager.executeQuery(relationQuery, { timestamp, }); // Convert relationships to relations const relations = relationResult.records.map((record) => { const rel = record.get('r').properties; const fromName = record.get('fromName'); const toName = record.get('toName'); return this.relationshipToRelation(rel, fromName, toName); }); const timeTaken = Date.now() - startTime; // Return the graph state at the timestamp return { entities, relations, total: entities.length, timeTaken, }; } catch (error) { logger.error(`Error retrieving graph state at timestamp ${timestamp} from Neo4j`, error); throw error; } }