OPC UA MCP Server

Overview

Python and TypeScript implementations provide the same core functionality for OPC UA operations through MCP tools, but differ in their implementation approach and deployment model.

Example Usage in Conversation

Once configured, you can ask Claude to perform real-world OPC UA operations:

Reading Sensor Values

• "What is the current temperature reading from the reactor vessel?"
• "Check the pressure level in Tank A"
• "Read all temperature sensors in the cooling system"
• "Get the current flow rate on production line B"

Controlling Equipment

• "Turn on the conveyor motor"
• "Set the mixer speed to 80 RPM"
• "Open valve V-101 to 75% position"
• "Start the circulation pump"
• "Set the heating element to 150°C"

Production Operations

• "Start production on line 1 with rate 100 units/hour"
• "Stop all motors in emergency mode"
• "Initialize the batch reactor with recipe A"
• "Begin the cleaning cycle for Tank B"

System Monitoring

• "Show me all alarm states in the system"
• "Read all sensor values from the water treatment plant"
• "Check the status of all pumps and motors"
• "Get the energy consumption readings"
• "Discover all available variables in the OPC UA server"
• "Show me a complete inventory of all sensors and actuators"

Real Example Scenarios

User: "What's the temperature in reactor R-101?"
Assistant: I'll read the temperature sensor for reactor R-101.
Tool call: read_opcua_node with node_id "ns=2;i=11"
Result: "Reactor R-101 temperature: 87.3°C"

User: "Turn on the main conveyor motor"
Assistant: I'll start the main conveyor motor for you.
Tool call: write_opcua_node with node_id "ns=2;i=12" and value "true"
Result: "Main conveyor motor started successfully"

User: "Set the pump speed to 65%"
Assistant: I'll adjust the pump speed to 65%.
Tool call: write_opcua_node with node_id "ns=2;i=13" and value "65"
Result: "Pump speed set to 65%"

User: "Show me all available variables in the system"
Assistant: I'll get a complete list of all variables in the OPC UA server.
Tool call: get_all_variables
Result: "Found 15 variables:
- Name: Temperature_Sensor_01, NodeID: ns=2;i=101, Value: 87.3°C
- Name: Pressure_Sensor_01, NodeID: ns=2;i=102, Value: 2.5 bar
- Name: Flow_Rate_01, NodeID: ns=2;i=103, Value: 125.8 L/min
..."

Implementation Languages

Python Version (opcua-mcp-server)

• Language: Python 3.13+
• Framework: FastMCP
• OPC UA Library: opcua (FreeOpcUa)
• Transport: STDIO
• Entry Point: opcua-mcp-server.py

NPX Version (opcua-mcp-npx-server)

• Language: TypeScript/Node.js
• Framework: @modelcontextprotocol/sdk
• OPC UA Library: node-opcua
• Transport: STDIO
• Entry Point: src/index.ts (compiled to build/index.js)

Features Comparison

Tool Implementations

Available Tools (Both Versions)

1. read_opcua_node

   • Read value from a single OPC UA node
   • Parameters: node_id (string)
   • Returns: Node value with ID prefix

2. write_opcua_node

   • Write value to a single OPC UA node
   • Parameters: node_id (string), value (string)
   • Returns: Success/failure message

3. browse_opcua_node_children

   • Browse children of an OPC UA node
   • Parameters: node_id (string)
   • Returns: Array of child nodes with IDs and browse names

4. read_multiple_opcua_nodes

   • Read values from multiple nodes in one request
   • Parameters: node_ids (array of strings)
   • Returns: Dictionary mapping node IDs to values

5. write_multiple_opcua_nodes

   • Write values to multiple nodes in one request
   • Parameters: nodes_to_write (array of {node_id, value} objects)
   • Returns: Status results for each write operation

6. call_opcua_method

   • Call a method on an OPC UA object
   • Parameters: object_node_id, method_node_id, arguments (optional)
   • Returns: Method execution result

7. get_all_variables

   • Get all available variables from the OPC UA server
   • Parameters: None
   • Returns: Comprehensive list of all variables with their properties (name, node ID, value, data type, description)

Deployment & Installation

Python Version

# Installation
cd opcua-mcp-server
uv install  # or pip install

# Usage
uv run opcua-mcp-server.py
# or
python opcua-mcp-server.py

NPX Version

# Direct usage (recommended)
npx opcua-mcp-npx-server

# Global installation
npm install -g opcua-mcp-npx-server
opcua-mcp-npx-server

# Development
npm install
npm run build
npm start

NPM Package: https://www.npmjs.com/package/opcua-mcp-npx-server

Configuration

Both versions use the same environment variable:

• OPCUA_SERVER_URL: OPC UA server endpoint (default: opc.tcp://localhost:4840)

Python Configuration Example

{
  "mcpServers": {
    "opcua-python": {
      "command": "/Users/mx/.local/bin/uv",
      "args": [
        "--directory",
        "/path/to/opcua-mcp-server",
        "run",
        "opcua-mcp-server.py"
      ],
      "env": {
        "OPCUA_SERVER_URL": "opc.tcp://localhost:4840"
      }
    }
  }
}

NPX Configuration Example

{
  "mcpServers": {
    "opcua-npx": {
      "command": "npx",
      "args": ["opcua-mcp-npx-server"],
      "env": {
        "OPCUA_SERVER_URL": "opc.tcp://localhost:4840"
      }
    }
  }
}

Dependencies

Python Version

• mcp[cli]>=1.9.1: MCP framework
• opcua>=0.98.13: OPC UA client library
• cryptography>=45.0.2: Security support
• httpx>=0.28.1: HTTP client

NPX Version

• @modelcontextprotocol/sdk: MCP SDK for Node.js
• node-opcua: Comprehensive OPC UA library
• typescript: TypeScript compiler
• @types/node: Node.js type definitions

Security

Both versions currently connect with:

• SecurityPolicy.None
• MessageSecurityMode.None

For production use, both should implement:

• Certificate-based authentication
• Encrypted communication
• User authentication
• Input validation