Db2 for i MCP Server

mcp-server-db2i is a Model Context Protocol (MCP) server for IBM Db2 for i (Db2i) on IBM i (AS/400). It 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 or Mapepire over SSH.

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

Website: db2i-mcp.com, with a blog that explains each release. Docs: docs.db2i-mcp.com.

Architecture

AI clients connect to the MCP Server in one of two ways. Local clients such as Claude Desktop, Claude Code and Cursor can start it as a process and talk over stdio. Remote clients connect over Streamable HTTP at /mcp, signing in with OAuth 2.1 (claude.ai custom connectors) or a bearer token (custom agents). Local clients can also use the HTTP endpoint. The server executes read-only queries against Db2 for i using the IBM i Access ODBC driver (default, no Java), the optional JT400 JDBC driver (DB2I_DRIVER=jt400), or Mapepire over SSH (DB2I_DRIVER=mapepire) for systems where only SSH is reachable. One server can reach several IBM i systems through connection profiles, each with its own driver.

graph LR
    subgraph clients ["AI Clients"]
        local("Claude Desktop, Claude Code, Cursor")
        remote("claude.ai connectors")
        agents("Custom Agents")
    end

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

    subgraph prod ["IBM i: prod"]
        db2prod[("Db2 for i")]
    end

    subgraph test ["IBM i: test"]
        db2test[("Db2 for i")]
    end

    subgraph dev ["IBM i: dev"]
        db2dev[("Db2 for i")]
    end

    local -->|local process| stdio
    local -.->|remote URL| http
    remote -->|OAuth 2.1| http
    agents -->|bearer token| http
    stdio & http --> tools
    tools --> profiles
    profiles --> odbc & jdbc & mapepire
    odbc -->|ODBC| db2prod
    jdbc -->|JDBC| db2test
    mapepire -->|SSH| db2dev

Features

• Read-only SQL queries - Execute SELECT statements safely with automatic result limiting, and a query timeout that cancels runaway statements on the IBM i
• 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 - MCP over Streamable HTTP with token authentication for remote clients and agents
• OAuth for Remote Clients - Built-in OAuth 2.1 sign-in with the user's own IBM i profile, so claude.ai custom connectors can connect. The sign-in page can carry your company's name, logo, colors and language (Customize for your company)
• 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
• SSH-only systems - With DB2I_DRIVER=mapepire, reach an IBM i where only SSH is open. Mapepire starts inside the SSH session, with no server install and a host key check. See Using the Mapepire driver
• 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
• Server instructions - Send the rules no query may miss, such as which flag marks a deleted row, to the model at the start of every session. See Instructions
• 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
• Query exports - Hand the user a CSV or Excel file of a query's results, as a file path over stdio or a short-lived download link over HTTP. The rows never pass through the model. See Query exports
• Audit log - Record every tool call and sign-in as one JSON line, with the SQL hashed by default. Optionally record the model's reason for each call (MCP_TOOL_INTENT). 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. The other drivers' packages are not installed by default, so add them next to the server:

npm install -g mcp-server-db2i node-jt400              # DB2I_DRIVER=jt400, needs a JDK to install and a JRE to run
npm install -g mcp-server-db2i @ibm/mapepire-js ssh2   # DB2I_DRIVER=mapepire, when only SSH reaches the IBM i

With npx, pass them with -p, for example npx -y -p mcp-server-db2i@latest -p node-jt400 mcp-server-db2i. See Installing the jt400 and mapepire packages.

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": ["-y", "mcp-server-db2i@latest"],
      "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

Tool	Description
execute_query	Execute read-only SELECT queries
export_query	Write every row of a read-only query to a CSV or XLSX file: a path over stdio, a short-lived download link over HTTP. Off unless EXPORT_ENABLED is set
list_schemas	List schemas/libraries (with optional filter)
list_tables	List tables in a schema (with optional filter)
search_tables	Find tables by name or description across libraries
search_columns	Find columns by name or description across libraries
describe_table	Get detailed column information
list_views	List views in a schema (with optional filter)
list_indexes	List SQL indexes for a table
get_table_constraints	Get primary keys, foreign keys, unique constraints
list_routines	List SQL procedures and functions in a library, with language, external program, and SQL data access
describe_routine	Parameters, return value or result columns, and a call template for a procedure or function
validate_query	Check a statement without running it, including catalog names
get_object_ddl	Return the SQL DDL that recreates an object
get_related_objects	List objects that depend on a table
get_journal_info	List journal, images, and primary key per table, and flag tables a replication tool cannot read
index_advice	List the indexes the query optimizer asked for in a library, merged and ranked by temporary index use
profile_table	Row count, last change, and per-column distinct and null counts from stored statistics or a scan
get_business_context	List business descriptions, row filters and relations loaded from YAML
search_ibmi_services	Find IBM i services by keyword or category, with the release that added each one and an example query

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.

Resource	Contents	Registered when
db2i://{schema}/{table}	Columns from the catalog, plus the YAML business description, column notes, and relations	describe_table is enabled
db2i://{schema}/{table}/ddl	SQL from QSYS2.GENERATE_SQL that recreates the table, view, or alias	get_object_ddl is enabled
db2i://business-context	Every annotation loaded from MCP_CUSTOM_TOOLS	get_business_context is enabled

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.

Prompt	Arguments	What it asks for
explore_library	schema	List the tables, describe the central ones, and summarize how they join
explain_table	schema, table	Explain rows, columns, keys, and relations in plain language
write_query	question, schema, table	Write one SELECT from the table's real columns and YAML relations, then validate and run it when those tools are enabled

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

Guide	Description
Tools, resources, and prompts	Built-in tools, filter syntax, MCP resources, and prompts
HTTP Transport	HTTP API, auth, and protocol versions
Configuration	All environment variables and driver options
Security	Credentials, rate limiting, query validation
Business SQL tools	YAML tools for orders, ledgers, and master data
Use cases	REST APIs, BI pipelines, replication, and ad-hoc analysis
Client Setup	Cursor, Claude, Claude Code setup
Docker Guide	Container deployment
Development	Contributing and local setup

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)
• search_ibmi_services needs QSYS2.SERVICES_INFO, which ships with the Db2 for i PTF group
• The cause and recovery on a failed statement come from SYSTOOLS.SQLCODE_INFO. Without it, errors return the SQLSTATE, SQLCODE and message only
• Node.js 22 or higher
• unixODBC with the IBM i Access ODBC Driver for the default odbc driver, a JDK at install time and a JRE 11 or higher at runtime for the optional jt400 driver, or SSH access and Java 8 or higher on the IBM i for the optional mapepire 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. This project's mapepire driver uses Mapepire's SSH mode, which needs no Mapepire server running on the IBM i.

Contributing

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

License

MIT License - see LICENSE for details.

Trademarks

IBM, IBM i and Db2 are trademarks of International Business Machines Corporation. This project is not affiliated with or endorsed by IBM.

Acknowledgments

• node-jt400 - JT400 JDBC driver wrapper for Node.js
• node-odbc - ODBC bindings for Node.js, maintained by IBM
• mapepire-js - Mapepire client 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)