MSSQL MCP Writer

Model Context Protocol server for Microsoft SQL Server with read and data operations.

Full data manipulation capabilities (INSERT, UPDATE, DELETE) with preview/confirm safeguards, but no DDL operations. Ideal for data engineers and ETL workflows where you need to modify data but want to prevent schema changes.

Architecture

This package is a thin wrapper around @connorbritain/mssql-mcp-core, which contains all shared logic, tools, and governance features. The wrapper selects the "writer" tier and delegates to the core's startMcpServer() function. This design enables:

• Hard separation at the package level — regulated enterprises can guarantee that certain builds physically cannot perform destructive operations
• Independent versioning — each tier can be published separately with its own release cycle
• Clear audit trail — "we only allow mssql-mcp-writer in staging" is a compile-time guarantee

The core library handles all SQL Server connections, tool dispatch, audit logging, and governance enforcement.

Package Tiers

| Package | npm | Tools | Use Case | |---------|-----|-------|----------| | mssql-mcp-reader | @connorbritain/mssql-mcp-reader | 14 read-only | Analysts, auditors, safe exploration | | mssql-mcp-writer (this) | @connorbritain/mssql-mcp-writer | 17 (reader + data ops) | Data engineers, ETL developers | | mssql-mcp-server | @connorbritain/mssql-mcp-server | 20 (all tools) | DBAs, full admin access |

Tools Included

| Category | Tools | |----------|-------| | Discovery | search_schema, describe_table, list_table, list_databases, list_environments | | Profiling | profile_table, inspect_relationships, inspect_dependencies, explain_query | | Data Read | read_data (SELECT only) | | Data Write | insert_data, update_data, delete_data (with preview/confirm) | | Scripts | list_scripts, run_script | | Operations | test_connection, validate_environment_config |

Not included: create_table, create_index, drop_table (DDL operations)

Quick Start

Install

npm install -g @connorbritain/mssql-mcp-writer@latest

MCP Client Configuration

{
  "mcpServers": {
    "mssql": {
      "command": "npx",
      "args": ["@connorbritain/mssql-mcp-writer@latest"],
      "env": {
        "SERVER_NAME": "127.0.0.1",
        "DATABASE_NAME": "mydb",
        "SQL_AUTH_MODE": "sql",
        "SQL_USERNAME": "app_user",
        "SQL_PASSWORD": "YourPassword123"
      }
    }
  }
}

Configuration

| Variable | Required | Notes | |----------|----------|-------| | SERVER_NAME | Yes | SQL Server hostname/IP | | DATABASE_NAME | Yes | Target database | | SQL_AUTH_MODE | | sql, windows, or aad (default: aad) | | SQL_USERNAME / SQL_PASSWORD | | Required for sql/windows modes | | READONLY | | true disables write tools | | ENVIRONMENTS_CONFIG_PATH | | Path to multi-environment JSON config | | SCRIPTS_PATH | | Path to named SQL scripts directory | | AUDIT_LOG_PATH | | Custom audit log path |

Features

All packages in the MSSQL MCP family share:

• Multi-environment support - Named database environments (prod, staging, dev) with per-environment policies
• Governance controls - allowedTools, deniedTools, allowedSchemas, deniedSchemas, requireApproval
• Audit logging - JSON Lines logs with session IDs and auto-redaction
• Secret management - ${secret:NAME} placeholders for secure credential handling
• Named SQL scripts - Pre-approved parameterized queries with governance controls
• Preview/confirm for mutations - update_data and delete_data show affected rows before execution

Documentation

Full documentation, configuration examples, and governance details are available in the main repository:

MSSQL MCP Server Documentation

License

MIT License. See LICENSE for details.

Repository: https://github.com/ConnorBritain/mssql-mcp-writer Issues: https://github.com/ConnorBritain/mssql-mcp-writer/issues npm: https://www.npmjs.com/package/@connorbritain/mssql-mcp-writer