MCP MariaDB Server
The MCP MariaDB Server provides a Model Context Protocol (MCP) interface for managing and querying MariaDB databases, supporting both standard SQL operations and advanced vector/embedding-based search. Designed for use with AI assistants, it enables seamless integration of AI-driven data workflows with relational and vector databases.
Table of Contents
Overview
The MCP MariaDB Server exposes a set of tools for interacting with MariaDB databases and vector stores via a standardized protocol. It supports:
- Listing databases and tables
- Retrieving table schemas
- Executing safe, read-only SQL queries
- Creating and managing vector stores for embedding-based search
- Integrating with embedding providers (currently OpenAI, Gemini, and HuggingFace) (optional)
Core Components
- server.py: Main MCP server logic and tool definitions.
- config.py: Loads configuration from environment and
.env files.
- embeddings.py: Handles embedding service integration (OpenAI).
- tests/: Manual and automated test documentation and scripts.
Available Tools
Standard Database Tools
Vector Store & Embedding Tools (optional)
Note: These tools are only available when EMBEDDING_PROVIDER is configured. If no embedding provider is set, these tools will be disabled.
-
create_vector_store
- Creates a new vector store (table) for embeddings.
- Parameters:
database_name, vector_store_name, model_name (optional), distance_function (optional, default: cosine)
-
delete_vector_store
- Deletes a vector store (table).
- Parameters:
database_name, vector_store_name
-
list_vector_stores
- Lists all vector stores in a database.
- Parameters:
database_name
-
insert_docs_vector_store
- Batch inserts documents (and optional metadata) into a vector store.
- Parameters:
database_name, vector_store_name, documents (list of strings), metadata (optional list of dicts)
-
search_vector_store
- Performs semantic search for similar documents using embeddings.
- Parameters:
database_name, vector_store_name, user_query (string), k (optional, default: 7)
Embeddings & Vector Store
Overview
The MCP MariaDB Server provides optional embedding and vector store capabilities. These features can be enabled by configuring an embedding provider, or completely disabled if you only need standard database operations.
Supported Providers
- OpenAI
- Gemini
- Open models from Huggingface
Configuration
EMBEDDING_PROVIDER: Set to openai, gemini, huggingface, or leave unset to disable
OPENAI_API_KEY: Required if using OpenAI embeddings
GEMINI_API_KEY: Required if using Gemini embeddings
HF_MODEL: Required if using HuggingFace embeddings (e.g., "intfloat/multilingual-e5-large-instruct" or "BAAI/bge-m3")
Model Selection
- Default and allowed models are configurable in code (
DEFAULT_OPENAI_MODEL, ALLOWED_OPENAI_MODELS)
- Model can be selected per request or defaults to the configured model
Vector Store Schema
A vector store table has the following columns:
id: Auto-increment primary key
document: Text of the document
embedding: VECTOR type (indexed for similarity search)
metadata: JSON (optional metadata)
Configuration & Environment Variables
All configuration is via environment variables (typically set in a .env file):
| Variable | Description | Required | Default |
|---|
DB_HOST | MariaDB host address | Yes | localhost |
DB_PORT | MariaDB port | No | 3306 |
DB_USER | MariaDB username | Yes | |
DB_PASSWORD | MariaDB password | Yes | |
DB_NAME | Default database (optional; can be set per query) | No | |
DB_CHARSET | Character set for database connection (e.g., cp1251) | No | MariaDB default |
DB_SSL | Enable SSL/TLS for database connection (true/false) | No | false |
DB_SSL_CA | Path to CA certificate file for SSL verification | No | |
DB_SSL_CERT | Path to client certificate file for SSL authentication | No | |
DB_SSL_KEY | Path to client private key file for SSL authentication | No | |
DB_SSL_VERIFY_CERT | Verify server certificate (true/false) | No | true |
DB_SSL_VERIFY_IDENTITY | Verify server hostname identity (true/false) | No | false |
MCP_READ_ONLY | Enforce read-only SQL mode (true/false) | No | true |
MCP_BLOCK_SENSITIVE_SHOW | Block sensitive SHOW commands (PROCESSLIST, GRANTS, VARIABLES, MASTER/REPLICA STATUS, BINARY LOGS, etc.) that can leak cross-connection query text, credentials/privileges, or replication topology. Set independently of MCP_READ_ONLY (true/false) | No | true |
MCP_MAX_POOL_SIZE | Max DB connection pool size | No | 10 |
EMBEDDING_PROVIDER | Embedding provider (openai/gemini/huggingface) | No | None(Disabled) |
OPENAI_API_KEY | API key for OpenAI embeddings | Yes (if EMBEDDING_PROVIDER=openai) | |
GEMINI_API_KEY | API key for Gemini embeddings | Yes (if EMBEDDING_PROVIDER=gemini) | |
HF_MODEL | Open models from Huggingface | Yes (if EMBEDDING_PROVIDER=huggingface) | |
ALLOWED_ORIGINS | Comma-separated list of allowed origins | No | Long list of allowed origins corresponding to local use of the server |
ALLOWED_HOSTS | Comma-separated list of allowed hosts | No | localhost,127.0.0.1 |
Note that if using 'http' or 'sse' as the transport, configuring authentication is important for security if you allow connections outside of localhost. Because different organizations use different authentication methods, the server does not provide a default authentication method. You will need to configure your own authentication method. Thankfully FastMCP provides a simple way to do this starting with version 2.12.1. See the FastMCP documentation for more information. We have provided an example configuration below.
Example .env file
With Embedding Support (OpenAI):
DB_HOST=localhost
DB_USER=your_db_user
DB_PASSWORD=your_db_password
DB_PORT=3306
DB_NAME=your_default_database
MCP_READ_ONLY=true
MCP_MAX_POOL_SIZE=10
EMBEDDING_PROVIDER=openai
OPENAI_API_KEY=sk-...
GEMINI_API_KEY=AI...
HF_MODEL="BAAI/bge-m3"
Without Embedding Support:
DB_HOST=localhost
DB_USER=your_db_user
DB_PASSWORD=your_db_password
DB_PORT=3306
DB_NAME=your_default_database
MCP_READ_ONLY=true
MCP_MAX_POOL_SIZE=10
With SSL/TLS Enabled:
DB_HOST=your-remote-host.com
DB_USER=your_db_user
DB_PASSWORD=your_db_password
DB_PORT=3306
DB_NAME=your_default_database
# Enable SSL
DB_SSL=true
DB_SSL_CA=~/.mysql/ca-cert.pem
DB_SSL_CERT=~/.mysql/client-cert.pem
DB_SSL_KEY=~/.mysql/client-key.pem
DB_SSL_VERIFY_CERT=true
DB_SSL_VERIFY_IDENTITY=false
MCP_READ_ONLY=true
MCP_MAX_POOL_SIZE=10
Note on SSL Configuration:
- All SSL certificate paths support
~ for home directory expansion
DB_SSL_CA is used to verify the server's certificate
DB_SSL_CERT and DB_SSL_KEY are used for client certificate authentication (mutual TLS)
- Set
DB_SSL_VERIFY_CERT=false only for testing with self-signed certificates
- Set
DB_SSL_VERIFY_IDENTITY=true to enable strict hostname verification
Example Authentication Configuration:
This configuration uses external web authentication via GitHub or Google. If you have internal JWT authentication (desired for organizations who manage their own services), you can use the JWT provider instead.
# GitHub OAuth
export FASTMCP_SERVER_AUTH=fastmcp.server.auth.providers.github.GitHubProvider
export FASTMCP_SERVER_AUTH_GITHUB_CLIENT_ID="Ov23li..."
export FASTMCP_SERVER_AUTH_GITHUB_CLIENT_SECRET="github_pat_..."
# Google OAuth
export FASTMCP_SERVER_AUTH=fastmcp.server.auth.providers.google.GoogleProvider
export FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_ID="123456.apps.googleusercontent.com"
export FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_SECRET="GOCSPX-..."
Database User Privileges - IMPORTANT
⚠️ The only way to guarantee 100% read-only access with absolute certainty is to configure the MariaDB user with appropriate privileges. The READ_ONLY flag is a best effort attempt to prevent write operations, but it is based upon a whitelist of allowed queries and against a truly adversarial user it is not a substitute for proper database user privileges.
For production use, you should create a dedicated database user with minimal privileges. This is also recommended to show the LLM only the data it may need to perform its task even outside of read-only mode.
Usage Examples
Standard SQL Query
{
"tool": "execute_sql",
"parameters": {
"database_name": "test_db",
"sql_query": "SELECT * FROM users WHERE id = %s",
"parameters": [123]
}
}
Create Vector Store
{
"tool": "create_vector_store",
"parameters": {
"database_name": "test_db",
"vector_store_name": "my_vectors",
"model_name": "text-embedding-3-small",
"distance_function": "cosine"
}
}
Insert Documents into Vector Store
{
"tool": "insert_docs_vector_store",
"parameters": {
"database_name": "test_db",
"vector_store_name": "my_vectors",
"documents": ["Sample text 1", "Sample text 2"],
"metadata": [{"source": "doc1"}, {"source": "doc2"}]
}
}
Semantic Search
{
"tool": "search_vector_store",
"parameters": {
"database_name": "test_db",
"vector_store_name": "my_vectors",
"user_query": "What is the capital of France?",
"k": 5
}
}
Integration - Claude desktop/Cursor/Windsurf/VSCode
Option 1: Direct Command (stdio)
{
"mcpServers": {
"MariaDB_Server": {
"command": "uv",
"args": [
"--directory",
"path/to/mariadb-mcp-server/",
"run",
"server.py"
],
"envFile": "path/to/mcp-server-mariadb-vector/.env"
}
}
}
Option 2: SSE Transport
{
"servers": {
"mariadb-mcp-server": {
"url": "http://{host}:9001/sse",
"type": "sse"
}
}
}
Option 3: HTTP Transport
{
"servers": {
"mariadb-mcp-server": {
"url": "http://{host}:9001/mcp",
"type": "streamable-http"
}
}
}
Option 4: Docker container
{
"servers": {
"mariadb-mcp-server": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"-p",
"9001:9001",
"-e",
"DB_HOST=",
"-e",
"DB_PORT=",
"-e",
"DB_USER=",
"-e",
"DB_PASSWORD=",
"-e",
"DB_NAME=",
"mariadb-mcp-server",
"python",
"src/server.py",
"--host",
"0.0.0.0",
"--transport",
"stdio"
]
}
}
}
Logging
- Logs are written to
logs/mcp_server.log by default.
- Log messages include tool calls, configuration issues, embedding errors, and client requests.
- Log level and output can be adjusted in the code (see
config.py and logger setup).
Testing
- Tests are located in the
src/tests/ directory.
- See
src/tests/README.md for an overview.
- Tests cover both standard SQL and vector/embedding tool operations.