mcp-server-db2i

A Model Context Protocol (MCP) server for IBM DB2 for i (DB2i). This server enables AI assistants like Claude and Cursor to query and inspect IBM i databases through the IBM i Access ODBC driver, or optionally the JT400 JDBC driver.

Listed in the MCP Registry as io.github.Strom-Capital/mcp-server-db2i.

Architecture

AI clients connect to the MCP Server via stdio (IDEs) or HTTP (agents), which executes read-only queries against DB2 for i using the IBM i Access ODBC driver (default, no Java) or the optional JT400 JDBC driver (DB2I_DRIVER=jt400). One server can reach several IBM i systems through connection profiles, each with its own driver.

graph LR
    subgraph clients ["AI Clients"]
        claude("Claude")
        cursor("Cursor IDE")
        agents("Custom Agents")
    end

    subgraph server ["MCP Server"]
        stdio["stdio"]
        http["HTTP + Auth"]
        tools[["MCP Tools"]]
        profiles{{"System profiles"}}
        odbc["IBM i Access ODBC"]
        jdbc["JT400 JDBC (optional)"]
    end

    subgraph prod ["IBM i: prod"]
        db2prod[("DB2 for i")]
    end

    subgraph test ["IBM i: test"]
        db2test[("DB2 for i")]
    end

    claude & cursor -->|MCP Protocol| stdio
    agents -->|REST API| http
    stdio & http --> tools
    tools --> profiles
    profiles --> odbc & jdbc
    odbc -->|ODBC| db2prod
    jdbc -->|JDBC| db2test

Features

• Read-only SQL queries - Execute SELECT statements safely with automatic result limiting
• Schema inspection - List all schemas/libraries with optional filtering
• Table metadata - List tables, describe columns, view indexes and constraints
• View inspection - List and explore database views
• Secure by design - Only SELECT queries allowed, credentials via environment variables
• Docker support - Run as a container for easy deployment
• HTTP Transport - REST API with token authentication for web/agent integration
• Current MCP spec - Speaks 2026-07-28 and still serves stateless 2025-era clients
• Dual Transport - Run stdio and HTTP simultaneously
• Multiple systems - Reach several IBM i systems from one server with DB2I_PROFILES, each with its own driver, credentials, and library allowlist. Tools take an optional system argument. See Multiple systems
• Tool selection - Enable or disable individual tools, e.g. a metadata-only mode without execute_query
• Business SQL tools - Load read-only ERP queries and table notes from YAML, and check the files with mcp-server-db2i validate-tools before the server starts. See Business SQL tools
• Compact responses - Compact JSON by default, or markdown tables to save tokens
• Statement checks and DDL - Validate object names, return the SQL that recreates an object, and list what depends on a table
• Catalog search and profiling - Find tables and columns across libraries, check journaling, and profile a table's row counts and value ranges
• Column masking - Redact sensitive columns, or show only their last four characters, in query results. See Column masking
• Audit log - Record every tool call as one JSON line, with the SQL hashed by default. See Audit log
• Tool reload - Reload YAML tool files when they change, with MCP_CUSTOM_TOOLS_WATCH=true
• Resources and prompts - Read table columns and DDL as MCP resources, and start from prompts that explore a library, explain a table, or write a query. See Resources and prompts

Quick Start

Installation

npm install -g mcp-server-db2i

The default odbc driver needs unixODBC and the IBM i Access ODBC Driver on the machine. No Java is needed. To use the JT400 JDBC driver instead, have a JDK installed when you run npm install and set DB2I_DRIVER=jt400. See Database Drivers.

Or with Docker:

docker build -t mcp-server-db2i .                  # odbc image (amd64; add --platform linux/amd64 on arm64)
docker build --target jt400 -t mcp-server-db2i .   # jt400 image (builds natively on arm64)

Configuration

Create a .env file with your IBM i credentials:

DB2I_HOSTNAME=your-ibm-i-host.com
DB2I_USERNAME=your-username
DB2I_PASSWORD=your-password
DB2I_SCHEMA=your-default-schema  # Optional

Client Setup

Add to your MCP client config (e.g., ~/.cursor/mcp.json):

{
  "mcpServers": {
    "db2i": {
      "command": "npx",
      "args": ["mcp-server-db2i"],
      "env": {
        "DB2I_HOSTNAME": "${env:DB2I_HOSTNAME}",
        "DB2I_USERNAME": "${env:DB2I_USERNAME}",
        "DB2I_PASSWORD": "${env:DB2I_PASSWORD}"
      }
    }
  }
}

This uses environment variable expansion to keep credentials out of config files. Set the variables in your shell profile (~/.zshrc or ~/.bashrc).

See the Client Setup Guide for Cursor, Claude Desktop, Claude Code, and Docker setup options.

Available Tools

Filter Syntax

The list tools support pattern matching:

• CUST - Contains "CUST"
• CUST* - Starts with "CUST"
• *LOG - Ends with "LOG"

Resources and prompts

Clients that support MCP resources can read a table's context without a tool call, and complete library and table names as you type.

resources/list offers the annotated tables, for example db2i://MYLIB/ORDERS. Percent-encode # and other reserved characters in names (ORD%23X for ORD#X). A library outside QUERY_ALLOWED_SCHEMAS is rejected with the same message execute_query gives, and completion offers only allowed libraries. Reads and completions that query IBM i count against the rate limit, and reads are written to the audit log. Completion fetches a library's name list once and reuses it for 60 seconds, so typing a name costs one query rather than one per keystroke.

A prompt is listed only when the tools it tells the model to call are enabled: explore_library needs list_tables and describe_table, and the other two need describe_table. None of them asks for a write.

Use cases

I've used this server on projects where the source system was the Iptor DC1 ERP on IBM i. The same patterns work with any IBM i ERP.

• Building REST APIs - The agent finds the ERP tables and keys, checks its SQL with validate_query, tests it on sample rows, and then writes the endpoint.
• ETL and ELT pipelines for BI - Profile source tables, generate staging DDL with get_object_ddl, and draft incremental extracts and code mappings for the warehouse.
• Near-real-time replication to BI - Check which tables are journaled, and with which images, before a journal-based tool such as Fivetran streams changes to the warehouse.
• Ad-hoc analysis - Connect Claude or Cursor directly to the ERP and ask business questions in plain language, with vetted Business SQL tools and column masking for sensitive fields.

See Use cases for sample prompts and the guardrails that go with each one.

Example Usage

Once connected, you can ask the AI assistant:

• "List all schemas that contain 'PROD'"
• "Show me the tables in schema MYLIB"
• "Describe the columns in MYLIB/CUSTOMERS"
• "What indexes exist on the ORDERS table?"
• "Run this query: SELECT * FROM MYLIB.CUSTOMERS WHERE STATUS = 'A'"
• "Find the order header and line tables in MYLIB and write a GET /orders/:orderNo endpoint"
• "Draft an incremental extract of MYLIB.ORDERHDR rows changed since yesterday"

Documentation

Compatibility

• IBM i V7R3 and later (V7R5 recommended)
• validate_query and the execute_query parse check need QSYS2.PARSE_STATEMENT (IBM i 7.3 with Db2 PTF group SF99703 level 3, or 7.4 and later)
• get_related_objects needs IBM i 7.3 Technology Refresh 9, IBM i 7.4 Technology Refresh 3, or a later release
• get_journal_info needs the journal columns of QSYS2.OBJECT_STATISTICS (IBM i 7.3 Technology Refresh 2 or later)
• Node.js 22 or higher
• unixODBC with the IBM i Access ODBC Driver for the default odbc driver, or a JDK at install time and a JRE 11 or higher at runtime for the optional jt400 driver (see Database Drivers)
• MCP spec 2026-07-28, plus stateless clients from the 2025-era revisions (through 2025-11-25)

Related Projects

• IBM ibmi-mcp-server - IBM's official MCP server for IBM i systems. Offers YAML-based SQL tool definitions and AI agent frameworks. Requires Mapepire.

Contributing

Contributions are welcome! See the Development Guide for setup instructions.

License

MIT License - see LICENSE for details.

Acknowledgments

• node-jt400 - JT400 JDBC driver wrapper for Node.js
• node-odbc - ODBC bindings for Node.js, maintained by IBM
• Model Context Protocol - The protocol specification
• @modelcontextprotocol/server - Official TypeScript SDK (spec 2026-07-28, with stateless 2025-era clients)