MCP Database Inspector

A powerful Model Context Protocol (MCP) server for inspecting MySQL and PostgreSQL database schemas, relationships, and structure. This tool provides AI assistants with comprehensive database introspection capabilities while maintaining strict read-only access for security.

🚀 Features

• Multi-Database Support: Connect to MySQL and PostgreSQL databases simultaneously
• SQL Query Analysis: Analyze query performance with EXPLAIN and get optimization recommendations
• Read-Only Database Inspection: Secure schema exploration without modification risks
• Comprehensive Schema Analysis: Detailed table, column, index, and relationship information
• Foreign Key Relationship Mapping: Understand data relationships across tables
• Index Performance Analysis: Identify optimization opportunities
• Security-First Design: Query validation, input sanitization, and audit logging
• Cross-Database Awareness: Analyze relationships across multiple database instances

📋 Requirements

• Node.js 18 or higher
• MySQL 5.7+ or PostgreSQL 12+ (or compatible databases)
• Network access to target database(s)
• Valid database credentials with SELECT permissions

📦 Installation

Global Installation

npm install -g mcp-database-inspector

Local Development

git clone https://github.com/kokorolx/mcp-mysql-inspector.git
cd mcp-mysql-inspector
npm install
npm run build

MCP Client Integration

Roo Configuration

Create roo-config.json:

{
  "servers": {
    "database-inspector": {
      "command": "npx",
      "args": [
        "mcp-database-inspector",
        "mysql://dev:password@localhost:3306/ecommerce",
        "postgresql://dev:password@localhost:5432/analytics"
      ]
    }
  }
}

Claude Desktop Configuration

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "database-inspector": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-database-inspector",
        "mysql://username:password@localhost:3306/database1",
        "postgresql://username:password@localhost:5432/database2"
      ]
    }
  }
}

🛠 Available Tools

1. list_databases

Lists all connected databases with connection status and type (MySQL/PostgreSQL).

2. list_tables

Lists all tables in a specified database with metadata.

3. inspect_table

Get complete table schema including columns, types, constraints, and metadata. Supports both single-table and multi-table inspection via the table (string) or tables (string[]) parameter.

Parameters:

• database (string, required): Name of the database.
• table (string, optional): Name of a single table to inspect.
• tables (string[], optional): Array of table names to inspect (multi-table mode).

Examples:

{ "database": "mydb", "table": "users" }
{ "database": "mydb", "tables": ["users", "orders", "products"] }

4. get_foreign_keys

Get foreign key relationships for one or more tables, or the entire database. Supports both single-table and multi-table inspection.

Parameters:

• database (string, required): Name of the database.
• table (string, optional): Name of a single table to analyze.
• tables (string[], optional): Array of table names to analyze (multi-table mode).

Examples:

{ "database": "mydb", "table": "orders" }
{ "database": "mydb", "tables": ["orders", "order_items"] }

5. get_indexes

Get detailed index information for one or more tables. Supports both single-table and multi-table inspection.

Parameters:

• database (string, required): Name of the database.
• table (string, optional): Name of a single table to analyze.
• tables (string[], optional): Array of table names to analyze (multi-table mode).

Examples:

{ "database": "mydb", "table": "products" }
{ "database": "mydb", "tables": ["products", "categories"] }

6. analyze_query ✨ NEW

Analyze SQL query performance using EXPLAIN and get optimization recommendations.

Parameters:

• database (string, required): Name of the database to run the analysis against.
• query (string, required): The SQL query to analyze.

Example:

{
  "database": "mydb",
  "query": "SELECT * FROM users WHERE email = '[email protected]'"
}

Response includes:

• Query cost estimation
• Execution plan operations
• Potential performance issues (e.g., full table scans)
• Actionable recommendations

7. execute_query

Execute safe, read-only SQL queries with automatic validation and row limits.

Parameters:

• database (string, required): Name of the database.
• query (string, required): The SQL query to execute.
• limit (number, optional): Maximum rows to return (default: 1000, max: 10000).

Example:

{
  "database": "mydb",
  "query": "SELECT id, name FROM users WHERE active = true",
  "limit": 100
}

8. information_schema_query

Query INFORMATION_SCHEMA tables with filters and limits.

Parameters:

• database (string, required): Name of the database.
• table (string, required): INFORMATION_SCHEMA table (COLUMNS, TABLES, or ROUTINES).
• filters (object, optional): Key-value filters for WHERE clause.
• limit (number, optional): Maximum rows to return (default: 100, max: 1000).

🔒 Security Features

Query Safety

• Whitelist-Only Approach: Only SELECT, SHOW, DESCRIBE, EXPLAIN queries allowed
• SQL Injection Prevention: Multi-layer validation and parameter binding
• Row Limits: Automatic limits to prevent resource exhaustion
• Timeout Protection: Query timeouts enforced

Input Validation

• URL Validation: Comprehensive connection string validation
• Identifier Sanitization: Database identifier format validation
• Parameter Sanitization: Input cleaning and null-byte removal

Audit & Logging

• Comprehensive Logging: All operations logged with configurable levels
• Sensitive Data Masking: Credentials automatically redacted from logs
• Performance Monitoring: Query timing and resource usage tracking

⚙️ Configuration

Environment Variables

| Variable | Description | Default | Example | |----------|-------------|---------|----------| | LOG_LEVEL | Logging level (error, warn, info, debug, trace) | info | LOG_LEVEL=debug |

Database URL Format

MySQL:

mysql://username:password@hostname:port/database?ssl=true

PostgreSQL:

postgresql://username:password@hostname:port/database?ssl=true
postgres://username:password@hostname:port/database

Supported Options:

• ssl=true/false - Enable/disable SSL connections

🚨 Troubleshooting

Common Issues

Connection Failures

# Test MySQL connection
mysql -h hostname -u username -p database_name

# Test PostgreSQL connection
psql -h hostname -U username -d database_name

# Check network connectivity
telnet hostname 3306  # MySQL
telnet hostname 5432  # PostgreSQL

Permission Errors

MySQL:

GRANT SELECT ON database_name.* TO 'username'@'%';
GRANT SELECT ON INFORMATION_SCHEMA.* TO 'username'@'%';

PostgreSQL:

GRANT CONNECT ON DATABASE database_name TO username;
GRANT USAGE ON SCHEMA public TO username;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO username;

Debug Mode

Enable detailed logging:

LOG_LEVEL=debug npx mcp-database-inspector "mysql://..." "postgresql://..."

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.