memento-mcp

Instructions

Implementation Reference

• src/server/handlers/listToolsHandler.ts:461-479 (registration)

  Registers the 'get_decayed_graph' tool and defines its input schema (optional reference_time and decay_factor).
  { name: 'get_decayed_graph', description: 'Get your Memento MCP knowledge graph memory with confidence values decayed based on time', inputSchema: { type: 'object', properties: { reference_time: { type: 'number', description: 'Optional reference timestamp (in milliseconds since epoch) for decay calculation', }, decay_factor: { type: 'number', description: 'Optional decay factor override (normally calculated from half-life)', }, }, }, },
• src/server/handlers/callToolHandler.ts:140-168 (handler)

  MCP CallTool handler for 'get_decayed_graph': parses arguments, calls KnowledgeGraphManager.getDecayedGraph() with options if provided, returns JSON stringified result.
  case 'get_decayed_graph': try { // Extract optional parameters if provided by client const options: { referenceTime?: number; decayFactor?: number; } = {}; if (args.reference_time) { options.referenceTime = Number(args.reference_time); } if (args.decay_factor) { options.decayFactor = Number(args.decay_factor); } // Pass options to getDecayedGraph if any are provided const graph = Object.keys(options).length > 0 ? await knowledgeGraphManager.getDecayedGraph(options) : await knowledgeGraphManager.getDecayedGraph(); 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 decayed graph: ${errorMessage}` }], }; }
• src/KnowledgeGraphManager.ts:1160-1166 (helper)

  KnowledgeGraphManager.getDecayedGraph(): checks if storageProvider supports it and delegates the call.
  async getDecayedGraph(): Promise<KnowledgeGraph & { decay_info?: Record<string, unknown> }> { if (!this.storageProvider || typeof this.storageProvider.getDecayedGraph !== 'function') { throw new Error('Storage provider does not support decay operations'); } return this.storageProvider.getDecayedGraph(); }
• src/storage/neo4j/Neo4jStorageProvider.ts:1603-1686 (handler)

  Core implementation of getDecayedGraph in Neo4jStorageProvider: loads current entities and relations, applies exponential decay to relation confidences based on age using configurable half-life and min confidence, adds decay_info diagnostics.
  async getDecayedGraph(): Promise<KnowledgeGraph> { try { // If decay is not enabled, just return the regular graph if (!this.decayConfig.enabled) { return this.loadGraph(); } const startTime = Date.now(); // Load entities const entityQuery = ` MATCH (e:Entity) WHERE e.validTo IS NULL RETURN e `; const entityResult = await this.connectionManager.executeQuery(entityQuery, {}); const entities = entityResult.records.map((record) => { const node = record.get('e').properties; return this.nodeToEntity(node); }); // Calculate decay factor const halfLifeMs = this.decayConfig.halfLifeDays * 24 * 60 * 60 * 1000; const decayFactor = Math.log(0.5) / halfLifeMs; // Load relations and apply decay const relationQuery = ` MATCH (from:Entity)-[r:RELATES_TO]->(to:Entity) WHERE r.validTo IS NULL RETURN r, from.name AS fromName, to.name AS toName `; const relationResult = await this.connectionManager.executeQuery(relationQuery, {}); const relations = relationResult.records.map((record) => { const rel = record.get('r').properties; const fromName = record.get('fromName'); const toName = record.get('toName'); // Create base relation const relation = this.relationshipToRelation(rel, fromName, toName); // Apply decay if confidence is present if (relation.confidence !== null && relation.confidence !== undefined) { const extendedRelation = relation as ExtendedRelation; const ageDiff = startTime - (extendedRelation.validFrom || extendedRelation.createdAt || startTime); let decayedConfidence = relation.confidence * Math.exp(decayFactor * ageDiff); // Don't let confidence decay below minimum if (decayedConfidence < this.decayConfig.minConfidence) { decayedConfidence = this.decayConfig.minConfidence; } relation.confidence = decayedConfidence; } return relation; }); const timeTaken = Date.now() - startTime; // Return the graph with decayed confidence values return { entities, relations, total: entities.length, timeTaken, diagnostics: { decay_info: { enabled: this.decayConfig.enabled, halfLifeDays: this.decayConfig.halfLifeDays, minConfidence: this.decayConfig.minConfidence, decayFactor, }, }, }; } catch (error) { logger.error('Error getting decayed graph from Neo4j', error); throw error; } }
• src/storage/StorageProvider.ts:148-148 (schema)

  StorageProvider interface definition for optional getDecayedGraph method.
  getDecayedGraph?(): Promise<KnowledgeGraph>;