OPC Foundation Updates Online Reference Update
The OPC UA Online Reference has been updated to address user feedback and make it more accessible to AI tools. The new site is live on the old URL (https://reference.opcfoundation.org/) and includes changes for human users, a MCP server for agentic AI and the ability to download the specification in different formats to use with offline LLMs.
User Interface Enhancements
The document view now has a left navigate panel that makes it easy to jump around the document while reading. It is also possible to access a single page view from the specification landing page that allow users use the browser to search the entire document.
All words italicized in the specification are linked to a search feature that puts the formal definition of the term at the top of the results when it is available. Buttons make it easy to limit scope of searches to the current specification, all core specification or the entire online references. Google site search is also available.
Links to sections are permanent URLs and can be stored. All links to sections on the previous website are redirected to the equivalent section (the site attempts to find the best match if the old link referred to an older version of the specification).
Every specification has a landing page that allows the use to see the version history, download the specification in different formats, download associated NodeSets or find the supplementary files on GitHub.
Agentic AI Support
The new website has a MCP server to support AI agents that access to OPC UA knowledge in their workflows. The MCP server is available at https://reference.opcfoundation.org/mcp and provides the following tools:
- search_text: Full-text search within a single OPC UA specification.
- search_nodes: Search for a definition based on a NodeId or BrowseName.
- search_cu: Search for a definition based on a Conformance Unit name.
- search_terms: Search for defined/italicized terms across OPC UA specifications.
Full text is not provided via the MCP API; only links to pages that can be accessed with HTTP.
LLM Training Support
Many OPC UA users are training specialized models and cannot depend on links to public internet. The new Online Reference provides multiple options include:
- XML: An XML syntax designed for technical specifications and used internally by the IEC;
- Markdown: A markdown file designed to provide the largest amount of information in the fewest number of tokens;
- JSONL: A RAG chunk format supported by local LLM frameworks such as Ollama. The chunks have metadata attached and are small enough to support common embedding models.
OPC Foundation welcomes suggestions on how to make these file formats more useful.
Continuous Improvement
The OPC Foundation wants the Online Reference to be as helpful as possible. Any issues or feature requests can be submitted here.