Opcua MCP

What kukapay/opcua-mcp MCP server does

The kukapay/opcua-mcp MCP server gives an MCP client access to data exposed by an OPC UA server. Its documented use cases include retrieving current values from industrial devices and writing values back to specified nodes. This makes it suitable for agent-assisted monitoring, operational analysis, and device control where the underlying equipment already provides an OPC UA interface.

The server works with individual nodes as well as multiple-node operations. A node is identified with an OPC UA node ID such as ns=2;i=2. Read operations return text containing the node identifier and its value. Write operations accept a value as text and convert it according to the target node's type, returning either a success message or an error.

How it works

An MCP-compatible client sends a tool request to the local server. The server connects to the OPC UA endpoint configured through OPCUA_SERVER_URL, performs the requested node operation, and returns the result to the client. Example interactions include asking for the value of a node or instructing the client to set a node to a specified value.

The README lists five exposed capabilities: reading one node, writing one node, browsing nodes, reading multiple nodes, and writing multiple nodes. The detailed parameter and return information is provided for the single-node read and write operations. The project description positions these operations for real-time access to industrial data, but the material does not specify subscription behavior, polling intervals, or event handling.

Setup and configuration

Using kukapay/opcua-mcp requires Python 3.13 or newer and access to an OPC UA server, such as a simulator or an industrial device. The documented setup is to clone the repository and install the Python dependencies with:

• mcp[cli]
• opcua
• cryptography

The MCP client configuration uses python as the command and points its arguments to the repository's opcua_mcp/main.py file. Set OPCUA_SERVER_URL in the client environment to the URL of the OPC UA server. The README shows a path and URL placeholder, so those values must be replaced with the local project path and actual endpoint.

Claude Desktop is explicitly listed as a compatible MCP client. The provided material does not document authentication settings, TLS options, certificate configuration, or connection retry behavior.

Tools and capabilities

• Read a specific OPC UA node using node_id.
• Write a value to a specific node using node_id and value.
• Browse OPC UA nodes.
• Read values from multiple nodes.
• Write values to multiple nodes.

For a single-node read, the response includes the node ID and its value. For a single-node write, the value is supplied as a string and converted based on the node type. The README does not provide parameter schemas or response examples for the browse and multiple-node capabilities beyond naming them as supported features.

Limitations and notes

This project depends on an accessible OPC UA server; it is not an OPC UA device simulator. The supplied documentation does not identify supported OPC UA security modes, credentials, certificates, namespaces beyond example node IDs, or the exact schemas for multi-node and browse requests. Validate write permissions and node data types in the target industrial environment before allowing an agent to perform control operations. The repository states that it is licensed under MIT.