Informix MCP Server

A Model Context Protocol server for IBM Informix databases. Connects via JDBC using jaydebeapi, so no Informix Client SDK installation is needed -- just a JDBC driver JAR and Java.

Prerequisites

Python 3.11+
uv (Python package manager)
Java 8+ (JDK or JRE)

An Informix JDBC driver JAR is bundled in the drivers/ directory. To use a different version, either replace the JAR in drivers/ or set the INFORMIX_JDBC_DRIVER_PATH environment variable.

Available Tools

Tool	Description
`test_connection`	Test connectivity and return the Informix server version
`list_databases`	List all databases on the server (queries `sysmaster:sysdatabases`)
`list_tables`	List user tables in a database, optionally including views and system tables
`describe_table`	Get column names, types, lengths, and nullability for a table
`execute_query`	Run arbitrary SQL with a configurable row limit
`get_table_indexes`	Show indexes on a table (name, type, clustered)
`get_table_constraints`	Show PK, FK, unique, and check constraints for a table

All tools accept an optional database parameter to target a specific database. If omitted, the default database from INFORMIX_DATABASE is used.

Setup

Cursor IDE

Add the following to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "informix": {
      "command": "/path/to/uv",
      "args": [
        "run",
        "--directory",
        "/path/to/informix-mcp",
        "informix-mcp-server.py"
      ],
      "env": {
        "JAVA_HOME": "/path/to/java/home",
        "INFORMIX_HOST": "your-host.example.com",
        "INFORMIX_PORT": "5020",
        "INFORMIX_DATABASE": "your_database",
        "INFORMIX_SERVER": "your_informix_server",
        "INFORMIX_USER": "your_user",
        "INFORMIX_PASSWORD": "your_password",
        "INFORMIX_DBDATE": "MDY4"
      }
    }
  }
}

After saving, restart the MCP server from Cursor Settings > MCP.

Claude Desktop

Add the following to your Claude Desktop config file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "informix": {
      "command": "/path/to/uv",
      "args": [
        "run",
        "--directory",
        "/path/to/informix-mcp",
        "informix-mcp-server.py"
      ],
      "env": {
        "JAVA_HOME": "/path/to/java/home",
        "INFORMIX_HOST": "your-host.example.com",
        "INFORMIX_PORT": "5020",
        "INFORMIX_DATABASE": "your_database",
        "INFORMIX_SERVER": "your_informix_server",
        "INFORMIX_USER": "your_user",
        "INFORMIX_PASSWORD": "your_password",
        "INFORMIX_DBDATE": "MDY4"
      }
    }
  }
}

After saving, restart Claude Desktop for the changes to take effect. The Informix tools will appear in the tools menu (hammer icon) when starting a new conversation.

Environment Variables

Variable	Required	Description
`JAVA_HOME`	Yes	Path to a JDK/JRE home directory
`INFORMIX_HOST`	Yes	Informix server hostname
`INFORMIX_PORT`	Yes	Informix SQLI port
`INFORMIX_DATABASE`	Yes	Default database name
`INFORMIX_SERVER`	Yes	Informix server instance name (`INFORMIXSERVER`)
`INFORMIX_USER`	Yes	Database username
`INFORMIX_PASSWORD`	Yes	Database password
`INFORMIX_DBDATE`	No	Date format (defaults to `MDY4`)
`INFORMIX_JDBC_DRIVER_PATH`	No	Override path to a JDBC driver JAR (defaults to bundled `drivers/*.jar`)

Running Standalone

# Install dependencies
uv sync

# Run (with env vars set)
uv run informix-mcp-server.py

The server communicates over stdio using the MCP protocol.

Switching Environments

To connect to a different Informix instance, update the env values in mcp.json with the new host, port, server name, database, and credentials. Restart the MCP server after changing environment variables.