CoreMCP

Model Context Protocol (MCP) server for database operations

CoreMCP by CoreBaseHQ provides a secure, extensible bridge between AI assistants (like Claude Desktop) and your databases through the Model Context Protocol.

🚀 Features

⚠️ Safety First: CoreMCP defaults to Read-Only mode — omitting readonly in your config is safe. We strongly recommend creating a specific database user with SELECT permissions only.

• 🔌 Multiple Database Support: MSSQL, Firebird (coming soon), and extensible adapter system
• 🧠 Automatic Schema Discovery: CoreMCP automatically scans your database tables, columns, foreign keys, and descriptions to provide AI context
• 📝 Column Comments Support: Extracts and presents database column comments/descriptions to the AI for better query understanding
• 🛠️ Dynamic Tool Generation: Built-in tools for common operations (list tables, describe schema) plus custom tool support
• 🎯 Custom Query Tools: Define reusable SQL queries as MCP tools in your config file
• 🛡️ NOLOCK / Read Uncommitted: Per-source option to run all SELECT queries under READ UNCOMMITTED isolation (MSSQL WITH (NOLOCK) equivalent) for zero-locking reads on busy OLTP databases
• 🛡️ Secure: Read-only mode support, connection string isolation
• 🎯 MCP Native: Built specifically for Model Context Protocol
• 🔧 Easy Configuration: Simple YAML-based setup
• 📦 Lightweight: Single binary, no runtime dependencies

📋 Requirements

• Go 1.23 or higher (for building from source)
• Database drivers are embedded in the binary

🔧 Installation

From Source

git clone https://github.com/corebasehq/coremcp.git
cd coremcp
go build -o coremcp ./cmd/coremcp

Binary Release

Download the latest release from the Releases page.

⚙️ Configuration

Create a coremcp.yaml file in your working directory:

server:
  name: "coremcp-agent"
  version: "0.1.0"
  transport: "stdio"
  port: 8080

logging:
  level: "info"
  format: "json"

sources:
  - name: "my_database"
    type: "mssql"
    dsn: "sqlserver://username:password@localhost:1433?database=mydb&encrypt=disable"
    readonly: true
    no_lock: true            # Optional: READ UNCOMMITTED isolation (WITH (NOLOCK) equivalent)
    normalize_turkish: true  # Optional: Turkish character normalization for legacy ERP databases

See coremcp.example.yaml for more examples.

DSN Format

Microsoft SQL Server:

sqlserver://username:password@host:port?database=dbname&encrypt=disable

Dummy (for testing):

dummy://test

Security Configuration

CoreMCP includes enterprise-grade security features:

security:
  # Maximum rows to return (prevents DB overload)
  max_row_limit: 1000
  
  # Enable PII masking
  enable_pii_masking: true
  
  # PII patterns to mask
  pii_patterns:
    - name: "credit_card"
      pattern: '\b\d{4}[\s-]?\d{4}[\s-]?\d{4}[\s-]?\d{4}\b'
      replacement: "****-****-****-****"
      enabled: true
    - name: "email"
      pattern: '\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b'
      replacement: "***@***.***"
      enabled: true
    - name: "turkish_id"
      pattern: '\b[1-9]\d{10}\b'
      replacement: "***********"
      enabled: true

Security Features:

• AST-Based Query Validation: Uses sqlparser to analyze SQL queries and block dangerous operations (DROP, ALTER, UPDATE, DELETE, TRUNCATE, EXEC, etc.)
• Automatic Row Limiting: Adds LIMIT clause to prevent accidentally returning millions of rows
• PII Data Masking: Automatically masks sensitive data like credit cards, emails, SSNs, Turkish IDs, IBANs
• Configurable Patterns: Define custom regex patterns for your specific PII requirements

Source Options

Option	Type	Default	Description
name	string	—	Unique source identifier
type	string	—	Adapter type: mssql, dummy
dsn	string	—	Connection string
readonly	bool	true	Restrict to SELECT-only at the config level. Set false explicitly to allow execute_procedure.
no_lock	bool	false	(MSSQL only) Run all SELECT queries under READ UNCOMMITTED transaction isolation level. Equivalent to adding WITH (NOLOCK) to every table reference. Eliminates shared lock acquisition, improving read throughput on busy OLTP databases. Trade-off: may return dirty (uncommitted) rows.
normalize_turkish	bool	false	(MSSQL only) Enable Turkish character normalization middleware. Outgoing: Turkish chars inside SQL string literals are converted to ASCII uppercase before the query is sent ('Hüseyin' → 'HUSEYIN', 'Şeker' → 'SEKER'). Incoming: Windows-1254 / Windows-1252 mojibake in result strings is auto-corrected. Use this for legacy Turkish ERP databases with Turkish_CI_AS collation.

Example: MSSQL with NOLOCK enabled

sources:
  - name: "oltp_db"
    type: "mssql"
    dsn: "sqlserver://user:pass@localhost:1433?database=production&encrypt=disable"
    readonly: true
    no_lock: true

Example: Legacy Turkish ERP Database

sources:
  - name: "erp_db"
    type: "mssql"
    dsn: "sqlserver://user:pass@localhost:1433?database=LOGO&encrypt=disable"
    readonly: true
    no_lock: true           # Avoid locking on busy OLTP
    normalize_turkish: true # AI can now search 'Hüseyin' and it matches 'HUSEYIN'

How Turkish normalization works:

AI sends	Normalized query (sent to DB)	Why
WHERE ADI = 'Hüseyin'	WHERE ADI = 'HUSEYIN'	ERP stores names as uppercase ASCII
WHERE SEHIR LIKE '%şeker%'	WHERE SEHIR LIKE '%SEKER%'	Ş → S
WHERE SEHIR = 'İstanbul'	WHERE SEHIR = 'ISTANBUL'	İ → I

Mojibake correction (incoming results):

DB returns (garbled)	Fixed output	Cause
GÐKHAN	GĞKHAN	Win-1254 byte 0xD0 read as Win-1252
ÝSTANBUL	İSTANBUL	Win-1254 byte 0xDD read as Win-1252
ÞEHİR	ŞEHİR	Win-1254 byte 0xDE read as Win-1252

🎯 Usage

CoreMCP has two operation modes:

1. Local Mode (serve) - For Claude Desktop

Start the MCP Server locally:

coremcp serve --config coremcp.yaml

Or use stdio transport (default):

coremcp serve -t stdio

Use with Claude Desktop

Add to your Claude Desktop config (claude_desktop_config.json):

{
  "mcpServers": {
    "coremcp": {
      "command": "/path/to/coremcp",
      "args": ["serve", "-c", "/path/to/coremcp.yaml"],
      "env": {}
    }
  }
}

2. Remote Mode (connect) - For SaaS & Factory Deployments 🚇

Connect to CoreBase Cloud Platform for remote management:

coremcp connect --server="wss://api.corebase.com/ws/agent" --token="sk_fabrika_123"

Perfect for:

• 🏭 Factory Deployments: No need to open inbound ports
• 🌐 Remote Management: Control databases from anywhere
• 🔐 Secure: Agent initiates connection from inside your network
• 🔄 Auto-Reconnect: Automatic reconnection on network failures
• ⚙️ Remote Config: Update database connections without redeployment

Connect Command Options

Flags:
  -s, --server string              CoreBase Cloud WebSocket URL (required)
  -t, --token string               Authentication token (required)
  -a, --agent-id string            Agent ID (optional, auto-generated if not provided)
  -r, --max-reconnect int          Maximum reconnection attempts (default: 10, 0 for infinite)
  -d, --reconnect-delay duration   Delay between reconnection attempts (default: 5s)

Example: Factory Deployment

# Factory IT admin runs this command
./coremcp connect \
  --server="wss://api.corebasehq.com/ws/agent" \
  --token="sk_fabrika_xyz" \
  --agent-id="factory-istanbul-001" \
  --max-reconnect=0  # Infinite reconnection

How it works:

1. 🔌 Agent connects to CoreBase Cloud via WebSocket (outbound only)
2. 🔐 Authenticates with your API token
3. 📡 Receives commands from your CoreBase dashboard
4. 🎯 Executes SQL queries on local databases
5. 📤 Sends results back through the secure tunnel
6. 🔄 Auto-reconnects on connection loss

Remote Commands Supported:

• run_sql: Execute SQL queries remotely
• get_schema: Retrieve database schema
• list_sources: List connected databases
• health_check: Check agent status
• config_sync: Update database configurations remotely

No Port Forwarding Required! 🎉

🏗️ Architecture

coremcp/
├── cmd/coremcp/       # CLI application entry point
│   ├── main.go        # Main entry
│   ├── root.go        # Root command
│   ├── serve.go       # Serve command (stdio mode for Claude Desktop)
│   └── connect.go     # Connect command (WebSocket mode for Cloud)
├── pkg/
│   ├── adapter/       # Database adapters
│   │   ├── factory.go # Adapter factory pattern
│   │   ├── dummy/     # Dummy adapter (for testing)
│   │   └── mssql/     # MSSQL adapter
│   ├── config/        # Configuration management
│   ├── core/          # Core type definitions
│   ├── security/      # Security features (PII masking, query validation)
│   └── server/        # MCP server implementation
└── coremcp.yaml       # Configuration file

🔌 Available Tools & Prompts

Built-in Tools

query_database

Executes arbitrary SQL queries on configured database sources.

Parameters:

• source_name (required): Name of the database source from config
• query (required): SQL query to execute

Example:

SELECT * FROM users WHERE id = 1

list_tables

Lists all tables in a database with summary information.

Parameters:

• source_name (required): Name of the database source

Returns: List of tables with column counts, primary keys, and foreign key counts.

describe_table

Shows detailed schema information for a specific table.

Parameters:

• source_name (required): Name of the database source
• table_name (required): Name of the table to describe

Returns: Complete table schema including:

• Column names and data types
• Nullable information
• Primary keys
• Foreign key relationships
• Column descriptions/comments

list_views

Lists all views in a database with their column definitions.

Parameters:

• source_name (required): Name of the database source

Returns: Each view with its column names, types, and nullability.

list_procedures

Lists all stored procedures in a database with parameter details.

Parameters:

• source_name (required): Name of the database source

Returns: Each procedure with parameter names, types, modes (IN/OUT/INOUT) and a ready-to-copy example call.

execute_procedure

Executes a stored procedure by name with optional named parameters.

⚠️ Only available on sources where readonly: false.

Parameters:

• source_name (required): Name of the database source
• procedure_name (required): Stored procedure name (e.g. sp_CiroHesapla)
• params (optional): JSON string of parameter name/value pairs

Security:

• Procedure name validated against ^[a-zA-Z_][a-zA-Z0-9_#@.]*$
• All values passed as named SQL parameters (sql.Named) — no string interpolation
• Parameter names also validated (alphanumeric + underscore only)
• Completely blocked when source is readonly: true

Example:

{
  "source_name": "erp_db",
  "procedure_name": "sp_CiroHesapla",
  "params": "{\"StartDate\":\"2024-01-01\",\"EndDate\":\"2024-12-31\"}"
}

Custom Tools

You can define reusable SQL queries as custom MCP tools in your coremcp.yaml:

custom_tools:
  - name: "get_daily_sales"
    description: "Retrieves daily sales summary for a specific date"
    source: "production_db"
    query: "SELECT * FROM orders WHERE DATE(created_at) = '{{date}}'"
    parameters:
      - name: "date"
        description: "Date in YYYY-MM-DD format"
        required: true

  - name: "get_top_customers"
    description: "Lists top N customers by order count"
    source: "production_db"
    query: "SELECT user_id, COUNT(*) as order_count FROM orders GROUP BY user_id ORDER BY order_count DESC LIMIT {{limit}}"
    parameters:
      - name: "limit"
        description: "Number of customers to return"
        required: true
        default: "10"

Benefits:

• Encapsulate complex queries
• Provide simple interfaces for common operations
• Parameters are automatically validated
• AI can discover and use these tools automatically

database_schema Prompt

Automatically provides complete database schema context to the AI, including:

• Table names
• Column names with data types
• Primary keys
• Foreign key relationships
• Column descriptions/comments from the database

When CoreMCP starts, it automatically:

1. Connects to all configured databases
2. Scans the schema (tables, columns, keys, relationships)
3. Extracts column comments/descriptions (e.g., MS_Description in MSSQL)
4. Creates a comprehensive context prompt for the AI

This allows Claude to understand your database structure and write accurate queries without you having to explain the schema manually.

Example: When you ask Claude "Show me all sales", Claude can see that you have a TBLSATIS table with specific columns and automatically write the correct query.

🛠️ Adding Custom Adapters

1. Create a new package in pkg/adapter/yourdb/
2. Implement the core.Source interface
3. Register in pkg/adapter/factory.go

See pkg/adapter/dummy/dummy.go for a simple example.

🤝 Contributing

Contributions are welcome! Please read CONTRIBUTING.md for details.

🔒 Security

For security concerns, please see SECURITY.md.

📄 License

Apache License 2.0 - see LICENSE for details.

🌟 Roadmap

• Automatic Schema Discovery - Load database structure on startup
• Column Comments/Descriptions - Extract and display database metadata
• Dynamic Tool Generation - list_tables, describe_table tools
• Custom Query Tools - Define reusable queries in config
• AST-Based Query Sanitization - Block dangerous SQL operations
• PII Data Masking - Mask sensitive information in results
• Automatic Row Limiting - Prevent database overload
• WebSocket Connect Mode - Remote management via CoreBase Cloud 🎉
• Auto-Reconnection Logic - Resilient agent connections
• Remote Configuration Sync - Update database configs remotely
• NOLOCK / Read Uncommitted - Per-source zero-locking reads for MSSQL
• Turkish Character Normalization - SQL literal normalization + mojibake fix for legacy Turkish ERP databases
• View & Stored Procedure Discovery - list_views, list_procedures, execute_procedure tools; auto-included in schema context
• PostgreSQL adapter
• MySQL adapter
• Firebird adapter (in progress)
• Query result caching
• HTTP transport support
• Write operation support (with strict safety guards)
• Audit logging
• Multi-tenant agent management
• Real-time monitoring dashboard

💬 Support

• 🐛 Report a bug
• 💡 Request a feature
• 📧 Email: support@corebasehq.com

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