🧠🕸️ AgensGraph Knowledge Graph Memory MCP Server

🌟 Overview

A Model Context Protocol (MCP) server implementation that provides persistent memory capabilities through AgensGraph graph database integration.

By storing information in a graph structure, this server maintains complex relationships between entities as memory nodes and enables long-term retention of knowledge that can be queried and analyzed across multiple conversations or sessions.

The MCP server leverages AgensGraph's graph database capabilities to create an interconnected knowledge base that serves as an external memory system. Through Cypher queries, it allows exploration and retrieval of stored information, relationship analysis between different data points, and generation of insights from the accumulated knowledge.

🕸️ Graph Schema

• Memory - A node representing an entity with a name, type, and observations.
• Relationship - A relationship between two entities with a type.

📦 Components

🔧 Tools

The server offers these core tools:

🔎 Query Tools

• read_graph

  • Read the knowledge graph
  • Input:
    • limit (int, optional): max entities to return (default 1000). Relations reference entities by name, so the result stays coherent when capped.
  • Returns: { "entities": [...], "relations": [...], "truncated": bool }. When truncated is true the memory has more — narrow with search_memories or raise the limit. (Default cap configurable via AGENSGRAPH_MEMORY_LIMIT.)

• search_memories

  • Search for nodes based on a query
  • Input:
    • query (string): Search query matching names, types, observations
    • limit (int, optional): max matching entities to return (default 1000)
  • Returns: matching subgraph as { "entities", "relations", "truncated" }

• find_memories_by_name

  • Find specific nodes by name
  • Input:
    • names (array of strings): Entity names to retrieve
  • Returns: Subgraph with specified nodes

♟️ Entity Management Tools

• create_entities

  • Create multiple new entities in the knowledge graph
  • Input:
    • entities: Array of objects with:
      • name (string): Name of the entity
      • type (string): Type of the entity
      • observations (array of strings): Initial observations about the entity
  • Returns: Created entities

• delete_entities

  • Delete multiple entities and their associated relations
  • Input:
    • entityNames (array of strings): Names of entities to delete
  • Returns: Success confirmation

🔗 Relation Management Tools

• create_relations

  • Create multiple new relations between entities
  • Input:
    • relations: Array of objects with:
      • source (string): Name of source entity
      • target (string): Name of target entity
      • relationType (string): Type of relation
  • Returns: Created relations

• delete_relations

  • Delete multiple relations from the graph
  • Input:
    • relations: Array of objects with same schema as create_relations
  • Returns: Success confirmation

📝 Observation Management Tools

• add_observations

  • Add new observations to existing entities
  • Input:
    • observations: Array of objects with:
      • entityName (string): Entity to add to
      • contents (array of strings): Observations to add
  • Returns: Added observation details

• delete_observations

  • Delete specific observations from entities
  • Input:
    • deletions: Array of objects with:
      • entityName (string): Entity to delete from
      • observations (array of strings): Observations to remove
  • Returns: Success confirmation

🔧 Usage with Claude Desktop

💾 Installation

pip install mcp-agensgraph-memory

⚙️ Configuration

Add the server to your claude_desktop_config.json:

"mcpServers": {
  "agensgraph": {
    "command": "uvx",
    "args": [
      "mcp-agensgraph-memory",
      "--db-url",
      "postgresql://localhost:5432",
      "--username",
      "<your-username>",
      "--password",
      "<your-password>",
      "--database",
      "<your-database>",
      "--graphname",
      "memory"
    ]
  }
}

Alternatively, you can set environment variables:

"mcpServers": {
  "agensgraph": {
    "command": "uvx",
    "args": [ "mcp-agensgraph-memory" ],
    "env": {
      "AGENSGRAPH_URL": "postgresql://localhost:5432",
      "AGENSGRAPH_USERNAME": "<your-username>",
      "AGENSGRAPH_PASSWORD": "<your-password>",
      "AGENSGRAPH_DATABASE": "<your-database>",
      "AGENSGRAPH_GRAPH_NAME": "memory"
    }
  }
}

Namespacing

For multi-tenant deployments, add --namespace to prefix tool names:

"args": [ "mcp-agensgraph-memory", "--namespace", "myapp", "--db-url", "..." ]

Tools become: myapp-read_graph, myapp-create_entities, etc.

Can also use AGENSGRAPH_NAMESPACE environment variable.

🌐 HTTP Transport Mode

The server supports HTTP transport for web-based deployments and microservices:

# Basic HTTP mode (defaults: host=127.0.0.1, port=8000, path=/mcp/)
mcp-agensgraph-memory --transport http

# Custom HTTP configuration
mcp-agensgraph-memory --transport http --server-host 127.0.0.1 --server-port 8080 --server-path /api/mcp/

Environment variables for HTTP configuration:

export AGENSGRAPH_TRANSPORT=http
export AGENSGRAPH_MCP_SERVER_HOST=127.0.0.1
export AGENSGRAPH_MCP_SERVER_PORT=8080
export AGENSGRAPH_MCP_SERVER_PATH=/api/mcp/
export AGENSGRAPH_NAMESPACE=myapp
mcp-agensgraph-memory

🔄 Transport Modes

The server supports three transport modes:

• STDIO (default): Standard input/output for local tools and Claude Desktop
• SSE: Server-Sent Events for web-based deployments
• HTTP: Streamable HTTP for modern web deployments and microservices

🔒 Security Protection

The server includes comprehensive security protection with secure defaults that protect against common web-based attacks while preserving full MCP functionality when using HTTP transport.

🛡️ DNS Rebinding Protection

TrustedHost Middleware validates Host headers to prevent DNS rebinding attacks:

Secure by Default:

• Only localhost and 127.0.0.1 hosts are allowed by default

Environment Variable:

export AGENSGRAPH_MCP_SERVER_ALLOWED_HOSTS="example.com,www.example.com"

🌐 CORS Protection

Cross-Origin Resource Sharing (CORS) protection blocks browser-based requests by default:

Environment Variable:

export AGENSGRAPH_MCP_SERVER_ALLOW_ORIGINS="https://example.com,https://app.example.com"

🔧 Complete Security Configuration

Development Setup:

mcp-agensgraph-memory --transport http \
  --allowed-hosts "localhost,127.0.0.1" \
  --allow-origins "http://localhost:3000"

Production Setup:

mcp-agensgraph-memory --transport http \
  --allowed-hosts "example.com,www.example.com" \
  --allow-origins "https://example.com,https://app.example.com"

🚀 Development

📦 Prerequisites

1. Install uv (Universal Virtualenv):

# Using pip
pip install uv

# Using Homebrew on macOS
brew install uv

# Using cargo (Rust package manager)
cargo install uv

2. Clone the repository and set up development environment:

# Create and activate virtual environment using uv
uv venv
source .venv/bin/activate  # On Unix/macOS
.venv\Scripts\activate     # On Windows

# Install dependencies including dev dependencies
uv sync

🔧 Environment Variables

Variable	Default	Description
AGENSGRAPH_URL	postgresql://localhost:5432	AgensGraph connection URL (host:port only)
AGENSGRAPH_USERNAME	agens	AgensGraph username
AGENSGRAPH_PASSWORD	agens	AgensGraph password
AGENSGRAPH_DB	agens	AgensGraph database name
AGENSGRAPH_GRAPH_NAME	memory	AgensGraph graph name
AGENSGRAPH_TRANSPORT	stdio (local), http (remote)	Transport protocol (stdio, http, or sse)
AGENSGRAPH_MCP_SERVER_HOST	127.0.0.1 (local)	Host to bind to
AGENSGRAPH_MCP_SERVER_PORT	8000	Port for HTTP/SSE transport
AGENSGRAPH_MCP_SERVER_PATH	/mcp/	Path for accessing MCP server
AGENSGRAPH_MCP_SERVER_ALLOW_ORIGINS	(empty - secure by default)	Comma-separated list of allowed CORS origins
AGENSGRAPH_MCP_SERVER_ALLOWED_HOSTS	localhost,127.0.0.1	Comma-separated list of allowed hosts (DNS rebinding protection)
AGENSGRAPH_NAMESPACE	(empty - no prefix)	Namespace prefix for tool names (e.g., myapp-read_graph)

📄 License

This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.