KnowledgeGraph MCP Server

What is KnowledgeGraph MCP Server?

KnowledgeGraph MCP Server gives LLMs persistent memory across conversations by storing and retrieving information via a knowledge graph. It lets Claude or VS Code remember user preferences, project details, and personal data using structured entities, relations, observations, and tags.

How to use KnowledgeGraph MCP Server?

Install the server via npx (npx knowledgegraph-mcp --help) or Docker (build from source). Choose SQLite (default, no setup) or PostgreSQL. Configure your client (Claude Desktop or VS Code) by adding the server definition to the MCP configuration file, optionally setting environment variables for storage type, connection strings, and search limits. Restart the client and test with commands like “Remember that I prefer morning meetings.”

Key features of KnowledgeGraph MCP Server

• Multiple storage backends: PostgreSQL (recommended) or SQLite (local file)
• Project separation: keep different projects isolated
• Better search: fuzzy search and pagination
• Entities, relations, observations, and tags for rich knowledge modeling
• Performance optimizations: entity loading limits and chunked processing
• Comprehensive input validation to prevent errors

Use cases of KnowledgeGraph MCP Server

• Remember user preferences (e.g., meeting times) across conversations
• Store and query project-related information (team members, technologies, deadlines)
• Track team structures with relations (e.g., “who leads which project”)
• Filter entities by tags for urgent or status-based queries
• Search for people, companies, or tasks using fuzzy matching

FAQ from KnowledgeGraph MCP Server

What storage backends are supported?

The server supports SQLite (default, no setup needed) and PostgreSQL (recommended for production with multiple concurrent users).

How do I configure the server for PostgreSQL?

Set the environment variables KNOWLEDGEGRAPH_STORAGE_TYPE=postgresql and KNOWLEDGEGRAPH_CONNECTION_STRING to your PostgreSQL connection string. Ensure the database knowledgegraph exists before starting.

Can I use the server with VS Code?

Yes. Add the server configuration to your VS Code User Settings (JSON) or .vscode/mcp.json using the same commands and environment variables as for Claude Desktop.

What environment variables control search behavior?

Variables include KNOWLEDGEGRAPH_SEARCH_MAX_RESULTS (default 100), KNOWLEDGEGRAPH_SEARCH_BATCH_SIZE (default 10), KNOWLEDGEGRAPH_SEARCH_MAX_CLIENT_ENTITIES (default 10000), and KNOWLEDGEGRAPH_SEARCH_CLIENT_CHUNK_SIZE (default 1000). All are clamped to safe ranges automatically.

Does the server automatically create the database?

For SQLite, the database file is created automatically in ~/.knowledge-graph/knowledgegraph.db. For PostgreSQL, you must create the knowledgegraph database manually before use.