mcp-sql

This MCP server provides read-only access to SQL databases across MySQL, MariaDB, PostgreSQL, SQLite, and SQL Server. It exposes two main tools you can invoke via the MCP client: query and schema. The query tool executes read-only SQL statements against a selected database connection and returns results encoded as TOON text payloads. The schema tool retrieves metadata about the database schema, including tables, columns, and other objects; use detail: full with includeViews and includeRoutines to obtain comprehensive definitions. The server supports PII redaction where configured, and you can enable this through the Database Configuration File by marking certain fields for redaction. Start the server using PHP (as shown in the installation steps) and connect your MCP client to the running instance; once connected, you can issue JSON-RPC like requests to query data or inspect schemas for any configured connection.

Prerequisites:

• PHP 8.4+ with required database extensions installed (depending on your databases: pdo_mysql, pdo_pgsql, pdo_sqlite, sqlsrv, etc.)
• Composer

Installation steps:

1. Clone the repository: git clone https://github.com/ineersa/mcp-sql-server.git cd mcp-sql-server

2. Install PHP dependencies (production only): composer install --no-dev

3. Create or provide your database configuration YAML file as described in the Documentation (e.g., databases.yaml) and set the DATABASE_CONFIG_FILE environment variable to its path.

4. Run the MCP server (example using built-in PHP server entrypoint via Symfony console): php bin/console mcp:server --port 8000

5. (Optional) If you prefer Docker, use the provided docker-compose.yaml from the Quick Start and follow the Docker-based setup in the README.

Notes:

• The exact command to start the server can vary depending on how you deploy (CLI Symfony command, PHP built-in server, or a container entrypoint). The example uses the Symfony-based command mcp:server which is typical for PHP/Symfony MCP servers.
• Ensure your database credentials in the YAML configuration are correct and that network access from the MCP server to the databases is permitted.

Tips and common considerations:

• Environment variables: DATABASE_CONFIG_FILE is required to locate the YAML file with database connections; APP_ENV, APP_DEBUG, and LOG_LEVEL control behavior and logging detail.
• For Docker deployments, the README provides a docker-compose example for running the MCP in a container alongside a database-mcp workflow; this is the recommended approach if you want isolated, reproducible environments.
• The MCP client configuration supports two primary tools (query and schema). Use query to fetch data from a specific connection and use schema to introspect the metadata of a connection before writing more complex queries.
• PII detection and redaction can be configured in your database configuration file; enabling redaction helps protect sensitive columns when returning results.
• If you run into PHP extension issues (e.g., missing PDO drivers), install the required PHP extensions corresponding to your target databases.
• Logs are written to APP_LOG_DIR; ensure the directory is writable by the web/User running the MCP server.