UA-.NETStandard/Applications/McpServer/README.md

OPC UA MCP Server

An MCP (Model Context Protocol) server that exposes OPC UA Part 4 service calls as MCP tools, enabling LLMs (Claude, Copilot, VS Code, etc.) to interact with OPC UA servers.

Features

• 64 MCP tools covering all OPC UA Part 4 service sets (except session management), plus PKI, configuration, NodeSet export, and OPC UA-aware packet capture
• Both stdio and HTTP/SSE transports
• JSON representation of all OPC UA types for LLM-friendly interactions
• Session management via Connect/Disconnect tools

Tool Inventory

Service Set	Tools	Description
Connection	GetEndpoints, Connect, Disconnect, GetConnectionStatus	Endpoint discovery and session lifecycle
Attribute	Read, Write, HistoryRead, HistoryUpdate	Read/write node attributes and historical data
View	Browse, BrowseNext, TranslateBrowsePaths, RegisterNodes, UnregisterNodes, QueryFirst, QueryNext	Navigate and query the address space
Node Management	AddNodes, AddReferences, DeleteNodes, DeleteReferences	Modify address space
Method	Call	Invoke methods
Subscription	CreateSubscription, ModifySubscription, SetPublishingMode, Publish, Republish, DeleteSubscriptions, TransferSubscriptions	Notification subscriptions
MonitoredItem	CreateMonitoredItems, ModifyMonitoredItems, SetMonitoringMode, SetTriggering, DeleteMonitoredItems	Data change monitoring
Discovery	FindServers, FindServersOnNetwork, RegisterServer, RegisterServer2	Server discovery and registration
PKI Management	ListCertificates, TrustCertificate, RemoveCertificate, GetPkiStorePaths	Manage certificate trust lists
Configuration	GetConfiguration, SetConfiguration	View/modify client settings for current session
NodeSet Export	ExportNodeSet, ExportNodeSetPerNamespace	Export address space to NodeSet2 XML
Convenience	ReadValue, ReadValues, WriteValue, BrowseAll, CallMethod, ReadNode, Cancel	Simplified operations
Packet Capture	list_interfaces, start_capture, stop_capture, list_captures, get_capture, capture_now, list_active_channels, dump_keys, decode_pcap_with_keys, summarize_service_calls, replay_pcap, stop_replay, list_replays	OPC UA-aware packet capture, offline decode, service-call summaries, replay

Documentation

See the full documentation and Nuget readme.

Claude Desktop Configuration

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "opcua": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/Applications/McpServer/Opc.Ua.Mcp.csproj"]
    }
  }
}

VS Code Configuration

Add to .vscode/mcp.json:

{
  "servers": {
    "opcua": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/Applications/McpServer/Opc.Ua.Mcp.csproj"]
    }
  }
}

Example Tool Calls

Connect to a server

Tool: Connect
Arguments:
  endpointUrl: "opc.tcp://localhost:62541/Quickstarts/ReferenceServer"
  useSecurity: true
  autoAcceptCerts: true

Browse the Objects folder

Tool: Browse
Arguments:
  nodeId: "i=85"

Read a variable value

Tool: ReadValue
Arguments:
  nodeId: "i=2258"

Write a value

Tool: WriteValue
Arguments:
  nodeId: "ns=2;s=MyVariable"
  value: "42"
  dataType: "Int32"

Call a method

Tool: CallMethod
Arguments:
  objectId: "ns=2;s=MyObject"
  methodId: "ns=2;s=MyMethod"
  inputArguments: ["arg1", "arg2"]

OPC UA Client Configuration

The server uses McpServer.Config.xml for OPC UA client configuration, including:

• Application certificate settings
• Trust list management
• Transport quotas
• Operation limits

Certificates are stored under %LocalApplicationData%/OPC Foundation/pki/.