index.ts•17.3 kB
#!/usr/bin/env node
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
CallToolRequestSchema,
ListToolsRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
import { promises as fs } from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';
// Define memory file path using environment variable with fallback
export const defaultMemoryPath = path.join(path.dirname(fileURLToPath(import.meta.url)), 'memory.jsonl');
// Handle backward compatibility: migrate memory.json to memory.jsonl if needed
export async function ensureMemoryFilePath(): Promise<string> {
if (process.env.MEMORY_FILE_PATH) {
// Custom path provided, use it as-is (with absolute path resolution)
return path.isAbsolute(process.env.MEMORY_FILE_PATH)
? process.env.MEMORY_FILE_PATH
: path.join(path.dirname(fileURLToPath(import.meta.url)), process.env.MEMORY_FILE_PATH);
}
// No custom path set, check for backward compatibility migration
const oldMemoryPath = path.join(path.dirname(fileURLToPath(import.meta.url)), 'memory.json');
const newMemoryPath = defaultMemoryPath;
try {
// Check if old file exists and new file doesn't
await fs.access(oldMemoryPath);
try {
await fs.access(newMemoryPath);
// Both files exist, use new one (no migration needed)
return newMemoryPath;
} catch {
// Old file exists, new file doesn't - migrate
console.error('DETECTED: Found legacy memory.json file, migrating to memory.jsonl for JSONL format compatibility');
await fs.rename(oldMemoryPath, newMemoryPath);
console.error('COMPLETED: Successfully migrated memory.json to memory.jsonl');
return newMemoryPath;
}
} catch {
// Old file doesn't exist, use new path
return newMemoryPath;
}
}
// Initialize memory file path (will be set during startup)
let MEMORY_FILE_PATH: string;
// We are storing our memory using entities, relations, and observations in a graph structure
export interface Entity {
name: string;
entityType: string;
observations: string[];
}
export interface Relation {
from: string;
to: string;
relationType: string;
}
export interface KnowledgeGraph {
entities: Entity[];
relations: Relation[];
}
// The KnowledgeGraphManager class contains all operations to interact with the knowledge graph
export class KnowledgeGraphManager {
constructor(private memoryFilePath: string) {}
private async loadGraph(): Promise<KnowledgeGraph> {
try {
const data = await fs.readFile(this.memoryFilePath, "utf-8");
const lines = data.split("\n").filter(line => line.trim() !== "");
return lines.reduce((graph: KnowledgeGraph, line) => {
const item = JSON.parse(line);
if (item.type === "entity") graph.entities.push(item as Entity);
if (item.type === "relation") graph.relations.push(item as Relation);
return graph;
}, { entities: [], relations: [] });
} catch (error) {
if (error instanceof Error && 'code' in error && (error as any).code === "ENOENT") {
return { entities: [], relations: [] };
}
throw error;
}
}
private async saveGraph(graph: KnowledgeGraph): Promise<void> {
const lines = [
...graph.entities.map(e => JSON.stringify({
type: "entity",
name: e.name,
entityType: e.entityType,
observations: e.observations
})),
...graph.relations.map(r => JSON.stringify({
type: "relation",
from: r.from,
to: r.to,
relationType: r.relationType
})),
];
await fs.writeFile(this.memoryFilePath, lines.join("\n"));
}
async createEntities(entities: Entity[]): Promise<Entity[]> {
const graph = await this.loadGraph();
const newEntities = entities.filter(e => !graph.entities.some(existingEntity => existingEntity.name === e.name));
graph.entities.push(...newEntities);
await this.saveGraph(graph);
return newEntities;
}
async createRelations(relations: Relation[]): Promise<Relation[]> {
const graph = await this.loadGraph();
const newRelations = relations.filter(r => !graph.relations.some(existingRelation =>
existingRelation.from === r.from &&
existingRelation.to === r.to &&
existingRelation.relationType === r.relationType
));
graph.relations.push(...newRelations);
await this.saveGraph(graph);
return newRelations;
}
async addObservations(observations: { entityName: string; contents: string[] }[]): Promise<{ entityName: string; addedObservations: string[] }[]> {
const graph = await this.loadGraph();
const results = observations.map(o => {
const entity = graph.entities.find(e => e.name === o.entityName);
if (!entity) {
throw new Error(`Entity with name ${o.entityName} not found`);
}
const newObservations = o.contents.filter(content => !entity.observations.includes(content));
entity.observations.push(...newObservations);
return { entityName: o.entityName, addedObservations: newObservations };
});
await this.saveGraph(graph);
return results;
}
async deleteEntities(entityNames: string[]): Promise<void> {
const graph = await this.loadGraph();
graph.entities = graph.entities.filter(e => !entityNames.includes(e.name));
graph.relations = graph.relations.filter(r => !entityNames.includes(r.from) && !entityNames.includes(r.to));
await this.saveGraph(graph);
}
async deleteObservations(deletions: { entityName: string; observations: string[] }[]): Promise<void> {
const graph = await this.loadGraph();
deletions.forEach(d => {
const entity = graph.entities.find(e => e.name === d.entityName);
if (entity) {
entity.observations = entity.observations.filter(o => !d.observations.includes(o));
}
});
await this.saveGraph(graph);
}
async deleteRelations(relations: Relation[]): Promise<void> {
const graph = await this.loadGraph();
graph.relations = graph.relations.filter(r => !relations.some(delRelation =>
r.from === delRelation.from &&
r.to === delRelation.to &&
r.relationType === delRelation.relationType
));
await this.saveGraph(graph);
}
async readGraph(): Promise<KnowledgeGraph> {
return this.loadGraph();
}
// Very basic search function
async searchNodes(query: string): Promise<KnowledgeGraph> {
const graph = await this.loadGraph();
// Filter entities
const filteredEntities = graph.entities.filter(e =>
e.name.toLowerCase().includes(query.toLowerCase()) ||
e.entityType.toLowerCase().includes(query.toLowerCase()) ||
e.observations.some(o => o.toLowerCase().includes(query.toLowerCase()))
);
// Create a Set of filtered entity names for quick lookup
const filteredEntityNames = new Set(filteredEntities.map(e => e.name));
// Filter relations to only include those between filtered entities
const filteredRelations = graph.relations.filter(r =>
filteredEntityNames.has(r.from) && filteredEntityNames.has(r.to)
);
const filteredGraph: KnowledgeGraph = {
entities: filteredEntities,
relations: filteredRelations,
};
return filteredGraph;
}
async openNodes(names: string[]): Promise<KnowledgeGraph> {
const graph = await this.loadGraph();
// Filter entities
const filteredEntities = graph.entities.filter(e => names.includes(e.name));
// Create a Set of filtered entity names for quick lookup
const filteredEntityNames = new Set(filteredEntities.map(e => e.name));
// Filter relations to only include those between filtered entities
const filteredRelations = graph.relations.filter(r =>
filteredEntityNames.has(r.from) && filteredEntityNames.has(r.to)
);
const filteredGraph: KnowledgeGraph = {
entities: filteredEntities,
relations: filteredRelations,
};
return filteredGraph;
}
}
let knowledgeGraphManager: KnowledgeGraphManager;
// The server instance and tools exposed to Claude
const server = new Server({
name: "memory-server",
version: "0.6.3",
}, {
capabilities: {
tools: {},
},
},);
server.setRequestHandler(ListToolsRequestSchema, async () => {
return {
tools: [
{
name: "create_entities",
description: "Create multiple new entities in the knowledge graph",
inputSchema: {
type: "object",
properties: {
entities: {
type: "array",
items: {
type: "object",
properties: {
name: { type: "string", description: "The name of the entity" },
entityType: { type: "string", description: "The type of the entity" },
observations: {
type: "array",
items: { type: "string" },
description: "An array of observation contents associated with the entity"
},
},
required: ["name", "entityType", "observations"],
additionalProperties: false,
},
},
},
required: ["entities"],
additionalProperties: false,
},
},
{
name: "create_relations",
description: "Create multiple new relations between entities in the knowledge graph. Relations should be in active voice",
inputSchema: {
type: "object",
properties: {
relations: {
type: "array",
items: {
type: "object",
properties: {
from: { type: "string", description: "The name of the entity where the relation starts" },
to: { type: "string", description: "The name of the entity where the relation ends" },
relationType: { type: "string", description: "The type of the relation" },
},
required: ["from", "to", "relationType"],
additionalProperties: false,
},
},
},
required: ["relations"],
additionalProperties: false,
},
},
{
name: "add_observations",
description: "Add new observations to existing entities in the knowledge graph",
inputSchema: {
type: "object",
properties: {
observations: {
type: "array",
items: {
type: "object",
properties: {
entityName: { type: "string", description: "The name of the entity to add the observations to" },
contents: {
type: "array",
items: { type: "string" },
description: "An array of observation contents to add"
},
},
required: ["entityName", "contents"],
additionalProperties: false,
},
},
},
required: ["observations"],
additionalProperties: false,
},
},
{
name: "delete_entities",
description: "Delete multiple entities and their associated relations from the knowledge graph",
inputSchema: {
type: "object",
properties: {
entityNames: {
type: "array",
items: { type: "string" },
description: "An array of entity names to delete"
},
},
required: ["entityNames"],
additionalProperties: false,
},
},
{
name: "delete_observations",
description: "Delete specific observations from entities in the knowledge graph",
inputSchema: {
type: "object",
properties: {
deletions: {
type: "array",
items: {
type: "object",
properties: {
entityName: { type: "string", description: "The name of the entity containing the observations" },
observations: {
type: "array",
items: { type: "string" },
description: "An array of observations to delete"
},
},
required: ["entityName", "observations"],
additionalProperties: false,
},
},
},
required: ["deletions"],
additionalProperties: false,
},
},
{
name: "delete_relations",
description: "Delete multiple relations from the knowledge graph",
inputSchema: {
type: "object",
properties: {
relations: {
type: "array",
items: {
type: "object",
properties: {
from: { type: "string", description: "The name of the entity where the relation starts" },
to: { type: "string", description: "The name of the entity where the relation ends" },
relationType: { type: "string", description: "The type of the relation" },
},
required: ["from", "to", "relationType"],
additionalProperties: false,
},
description: "An array of relations to delete"
},
},
required: ["relations"],
additionalProperties: false,
},
},
{
name: "read_graph",
description: "Read the entire knowledge graph",
inputSchema: {
type: "object",
properties: {},
additionalProperties: false,
},
},
{
name: "search_nodes",
description: "Search for nodes in the knowledge graph based on a query",
inputSchema: {
type: "object",
properties: {
query: { type: "string", description: "The search query to match against entity names, types, and observation content" },
},
required: ["query"],
additionalProperties: false,
},
},
{
name: "open_nodes",
description: "Open specific nodes in the knowledge graph by their names",
inputSchema: {
type: "object",
properties: {
names: {
type: "array",
items: { type: "string" },
description: "An array of entity names to retrieve",
},
},
required: ["names"],
additionalProperties: false,
},
},
],
};
});
server.setRequestHandler(CallToolRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
if (name === "read_graph") {
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.readGraph(), null, 2) }] };
}
if (!args) {
throw new Error(`No arguments provided for tool: ${name}`);
}
switch (name) {
case "create_entities":
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.createEntities(args.entities as Entity[]), null, 2) }] };
case "create_relations":
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.createRelations(args.relations as Relation[]), null, 2) }] };
case "add_observations":
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.addObservations(args.observations as { entityName: string; contents: string[] }[]), null, 2) }] };
case "delete_entities":
await knowledgeGraphManager.deleteEntities(args.entityNames as string[]);
return { content: [{ type: "text", text: "Entities deleted successfully" }] };
case "delete_observations":
await knowledgeGraphManager.deleteObservations(args.deletions as { entityName: string; observations: string[] }[]);
return { content: [{ type: "text", text: "Observations deleted successfully" }] };
case "delete_relations":
await knowledgeGraphManager.deleteRelations(args.relations as Relation[]);
return { content: [{ type: "text", text: "Relations deleted successfully" }] };
case "search_nodes":
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.searchNodes(args.query as string), null, 2) }] };
case "open_nodes":
return { content: [{ type: "text", text: JSON.stringify(await knowledgeGraphManager.openNodes(args.names as string[]), null, 2) }] };
default:
throw new Error(`Unknown tool: ${name}`);
}
});
async function main() {
// Initialize memory file path with backward compatibility
MEMORY_FILE_PATH = await ensureMemoryFilePath();
// Initialize knowledge graph manager with the memory file path
knowledgeGraphManager = new KnowledgeGraphManager(MEMORY_FILE_PATH);
const transport = new StdioServerTransport();
await server.connect(transport);
console.error("Knowledge Graph MCP Server running on stdio");
}
main().catch((error) => {
console.error("Fatal error in main():", error);
process.exit(1);
});