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