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Open Ontologies

Open Ontologies is an MCP server that adds search and knowledge tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Plan, apply and roll back changes to a production ontology, with a blast radius report… It has 816 GitHub stars, is released under the MIT license and runs locally with docker run -i --rm ghcr.io/fabio-rovai/open-ontologies.

github.com/fabio-rovai/open-ontologies (opens in a new tab)

Install Open Ontologies

Generated from the server's published package. Replace your-value with your own values.

Claude Desktop

claude_desktop_config.json
{
  "mcpServers": {
    "open-ontologies": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/fabio-rovai/open-ontologies"
      ]
    }
  }
}

Settings > Developer > Edit Config. macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\. Restart Claude Desktop afterwards.

Claude Code

claude mcp add --transport stdio open-ontologies -- docker run -i --rm ghcr.io/fabio-rovai/open-ontologies

Cursor

.cursor/mcp.json
{
  "mcpServers": {
    "open-ontologies": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/fabio-rovai/open-ontologies"
      ]
    }
  }
}

Project file; use ~/.cursor/mcp.json to enable it in every project.

VS Code

.vscode/mcp.json
{
  "servers": {
    "open-ontologies": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/fabio-rovai/open-ontologies"
      ]
    }
  }
}

Config formats checked against the official docs on Oct 7, 2026: modelcontextprotocol.io (opens in a new tab), code.claude.com (opens in a new tab), cursor.com (opens in a new tab), code.visualstudio.com (opens in a new tab).

About Open Ontologies

Plan a change to a production ontology. See every consequence before you apply it. Then give the reviewer a proof that they can check without trust in you. Open Ontologies is written in Rust. It ships as one binary.

  • ai-native
  • description-logics
  • knowledge-graph
  • mcp
  • mcp-server
  • ontology
  • owl
  • owl2
  • reasoning
  • rust

FAQ

Open Ontologies FAQ

Still curious? Email info@appsgit.com.

What is Open Ontologies?

Open Ontologies is an MCP server that adds search and knowledge tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Plan, apply and roll back changes to a production ontology, with a blast radius report… It has 816 GitHub stars, is released under the MIT license and runs locally with docker run -i --rm ghcr.io/fabio-rovai/open-ontologies. The source code is at github.com/fabio-rovai/open-ontologies.

How do I install the Open Ontologies MCP server?

Add the command docker run -i --rm ghcr.io/fabio-rovai/open-ontologies to your MCP client: put it in claude_desktop_config.json for Claude Desktop, run claude mcp add for Claude Code, or add it to .cursor/mcp.json (Cursor) or .vscode/mcp.json (VS Code). The snippets on this page are ready to paste.

Is Open Ontologies free?

The server is open source under the MIT license, so running it is free. It does not declare any required API key.

Is Open Ontologies actively maintained?

The most recent commit was on Oct 1, 2026. The latest release is v2.0.1, published Sep 28, 2026. appsgit only lists MCP servers with a commit in the last six months and re-checks every server daily.