node-opcua-modeler-mcp-server

An MCP server that gives AI agents access to the OPC UA companion specification type system — 589 types across 22 industrial namespaces, plus 1,533 engineering units — and lets agents validate, generate, and reverse-engineer OPC UA information models.

Built on node-opcua, the most widely used OPC UA stack for Node.js.

Why?

When an AI agent needs to build an OPC UA information model, it must know:

• What companion spec types exist (DI, Machinery, Robotics, Machine Tools…)
• What components, properties, and methods each type has
• What namespace dependencies are required
• What engineering unit symbols are valid (UNECE Rec. 20)

This MCP server answers all of those questions — offline, for free, in milliseconds.

Quick Start

With Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "opcua-modeler": {
      "command": "npx",
      "args": ["-y", "node-opcua-modeler-mcp-server"],
      "env": {
        "OPCUA_MODELER_API_KEY": "stfv_your_api_key_here"
      }
    }
  }
}

Note: The API key is optional for discovery tools (offline) and opcua_model_validate (5 free calls/day). It is required for opcua_model_generate and opcua_model_reverse. Get a free key at opcua-modeler.sterfive.com.

With any MCP client

npx node-opcua-modeler-mcp-server

The server communicates over stdio using the Model Context Protocol.

Tools

list_namespaces

List all 25 OPC UA companion spec namespaces with aliases, URIs, and dependencies.

→ list_namespaces()
← [
    { "alias": "di", "name": "OPC UA for Devices", "uri": "http://opcfoundation.org/UA/DI/", "dependencies": [] },
    { "alias": "robotics", "name": "OPC UA for Robotics", "uri": "http://opcfoundation.org/UA/Robotics/", "dependencies": ["di", "ia"] },
    ...
  ]

resolve_dependencies

Resolve the full dependency chain for companion spec aliases. Returns a topologically sorted list for the YAML namespaces: block.

→ resolve_dependencies({ aliases: ["machineTool"] })
← ["di", "ia", "machinery", "isa95JobControl", "machineryJobs", "machineTool"]

list_types

List all ObjectTypes and VariableTypes defined in a companion spec namespace.

→ list_types({ alias: "robotics" })
← [
    { "browseName": "MotionDeviceType", "kind": "ObjectType", "subtypeOf": "di:ComponentType", ... },
    { "browseName": "AxisType", "kind": "ObjectType", "subtypeOf": "di:ComponentType", ... },
    ...
  ]   // 25 types

get_type_details

Get the full structure of a type — components, properties, methods, interfaces, including inherited members.

→ get_type_details({ alias: "robotics", browseName: "MotionDeviceType" })
← {
    "browseName": "MotionDeviceType",
    "kind": "ObjectType",
    "subtypeOf": "di:ComponentType",
    "interfaces": ["di:IVendorNameplateType", "di:ITagNameplateType"],
    "components": [
      { "browseName": "robotics:Axes", "nodeClass": "Object", "typeDefinition": "FolderType", "modellingRule": "Mandatory" },
      { "browseName": "robotics:PowerTrains", "nodeClass": "Object", "typeDefinition": "FolderType", "modellingRule": "Mandatory" },
      ...
    ],
    "properties": [
      { "browseName": "di:Manufacturer", "dataType": "LocalizedText", "modellingRule": "Mandatory" },
      { "browseName": "robotics:MotionDeviceCategory", "dataType": "MotionDeviceCategoryEnumeration", "modellingRule": "Mandatory" },
      ...
    ]
  }

search_types

Search for types across all companion specs by keyword.

→ search_types({ query: "temperature" })
← [
    { "alias": "glass", "browseName": "MotorTemperatureTooHighEventType", ... },
    { "alias": "padim", "browseName": "TemperatureMeasurementVariableType", ... },
    { "alias": "amb", "browseName": "OverTemperatureConditionClassType", ... }
  ]

find_engineering_unit

Find the official UNECE Rec. 20 engineering unit symbol. Supports fuzzy matching and natural language aliases.

→ find_engineering_unit({ query: "celsius" })
← { "symbol": "°C", "matchType": "alias", "confidence": 1 }

→ find_engineering_unit({ query: "revolutions per minute" })
← { "symbol": "rpm", "matchType": "alias", "confidence": 1 }

→ find_engineering_unit({ query: "bar" })
← { "symbol": "bar", "matchType": "exact", "confidence": 1 }

opcua_model_validate ☁️

Validate an OPC UA YAML model for correctness. Returns diagnostics with severity, codes, messages, and line numbers. Works without an API key (limited to 5 calls/day).

→ opcua_model_validate({ yaml: "namespaces:\n  di:\n..." })
← {
    "valid": true,
    "diagnostics": [
      { "severity": "warning", "code": "W001", "message": "...", "line": 42 }
    ]
  }

opcua_model_generate ☁️

Generate OPC UA NodeSet2.xml and Symbols.CSV from a validated YAML model. Returns base64-encoded artifacts. Requires an API key.

→ opcua_model_generate({ yaml: "namespaces:\n  di:\n...", include_docs: false })
← {
    "valid": true,
    "artifacts": {
      "nodeset2_xml": "PD94bWwg...",
      "symbols_csv": "bmFtZSxu..."
    },
    "diagnostics": []
  }

opcua_model_reverse ☁️

Reverse-engineer a NodeSet2.xml file back into the YAML DSL format. Requires an API key.

→ opcua_model_reverse({ xml: "<?xml version=..." })
← {
    "yaml": "namespaces:\n  di:\n...",
    "diagnostics": []
  }

Coverage

Companion Specifications (25)

Alias	Specification	Types
padim	OPC UA for PA-DIM	101
ijtBase	OPC UA for IJT Base	65
machineTool	OPC UA for Machine Tools	63
di	OPC UA for Devices	44
glass	OPC UA for Glass Manufacturing	36
machineVision	OPC UA for Machine Vision	36
adi	OPC UA for Analyzer Devices	35
commercialKitchenEquipment	OPC UA for Commercial Kitchen Equipment	35
robotics	OPC UA for Robotics	25
ia	OPC UA for Industrial Automation	20
amb	OPC UA for AMB	18
autoId	OPC UA for AutoID	18
metalForming	OPC UA for Metal Forming	16
machinery	OPC UA for Machinery	15
gds	OPC UA GDS	14
woodworking	OPC UA for Woodworking	13
cnc	OPC UA for CNC Systems	12
	…and 5 more
Total	22 namespaces	589 types

Engineering Units

1,533 official UNECE Rec. 20 symbols plus 134 natural language aliases (e.g., "celsius" → °C, "revolutions per minute" → rpm).

How It Works

The server ships with a pre-generated catalog.json containing all type information extracted from OPC Foundation's official NodeSet2.xml files via node-opcua. All queries are answered from this static catalog — no network required, no API key needed.

┌──────────────────────────────────────────────────┐
│  node-opcua-modeler-mcp-server                   │
│                                                  │
│  LOCAL TOOLS (offline, free)                      │
│  ┌────────────────────────────────────────┐       │
│  │ catalog.json (1.7 MB)                  │       │
│  │ • 25 companion spec registries         │       │
│  │ • 589 type summaries + details         │       │
│  │ • 1,533 engineering units              │       │
│  └────────────────────────────────────────┘       │
│  6 tools → query the catalog                     │
│                                                  │
│  CLOUD TOOLS (via api.opcua-modeler.sterfive.io) │
│  3 tools → validate / generate / reverse         │
│                                                  │
│  stdio transport (JSON-RPC)                      │
└──────────────────────────────────────────────────┘

Use Cases

• AI-assisted OPC UA modeling — agents can discover types, resolve dependencies, and validate unit symbols before generating YAML/XML models
• Copilot integration — add OPC UA awareness to coding assistants
• Industrial digital twin design — explore companion spec type hierarchies interactively
• Learning OPC UA — ask an AI to explain types and their relationships

Requirements

• Node.js ≥ 18

Related

• node-opcua — Full OPC UA stack for Node.js
• OPC UA Modeler — Create, validate, and generate OPC UA information models
• Model Context Protocol — Open protocol for AI tool integration

License

MIT © Sterfive