Add it to Claude Code
claude mcp add open-ontologies -- /path/to/open-ontologies serveMake your agent remember this setup
open-ontologies's config, env vars, and the gotchas you hit — recalled in every future Claude Code, Cursor, and Codex session.
npx conare@latestFree · one command · indexes the sessions already on disk. Set up in the browser instead →
What it does
- In-memory Oxigraph triple store for high-performance RDF/OWL operations
- 48 specialized tools for ontology engineering and knowledge graph governance
- Terraform-style lifecycle management for ontologies
- Full lineage audit trail for all knowledge graph changes
- Support for semantic embeddings and standard ontology marketplaces
Tools 1
onto_*A suite of 48 tools for building, validating, querying, diffing, linting, versioning, and reasoning over RDF/OWL ontologies.Try it
Original README from fabio-rovai/open-ontologies
<strong>A Terraforming MCP for Knowledge Graphs</strong> Validate, classify, and govern AI-generated ontologies. Written in Rust. Ships as a single binary.
Quick Start · Studio · Benchmarks · Tools · Architecture · Docs
Open Ontologies is a Rust MCP server and desktop Studio for AI-native ontology engineering. It exposes 48 tools that let Claude build, validate, query, diff, lint, version, reason over, align, and persist RDF/OWL ontologies using an in-memory Oxigraph triple store — with Terraform-style lifecycle management, a marketplace of 29 standard ontologies, clinical crosswalks, semantic embeddings, and a full lineage audit trail.
The Studio wraps the engine in a visual desktop environment: 3D force-directed graph, AI chat panel, Protégé-style property inspector, and lineage viewer.
No JVM. No Protégé. No GUI required.
Screenshots
| Full UI | 3D Graph |
|---|---|
 |
 |
Tissue ontology built in natural language. Gold edges show object property relationships (domain → range) connecting clusters; grey edges show subClassOf hierarchy. Spring-based force layout keeps related classes close.
Quick Start (MCP / CLI)
Install
Pre-built binaries:
# macOS (Apple Silicon)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-aarch64-apple-darwin
chmod +x open-ontologies-aarch64-apple-darwin && mv open-ontologies-aarch64-apple-darwin /usr/local/bin/open-ontologies
# macOS (Intel)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-x86_64-apple-darwin
chmod +x open-ontologies-x86_64-apple-darwin && mv open-ontologies-x86_64-apple-darwin /usr/local/bin/open-ontologies
# Linux (x86_64)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-x86_64-unknown-linux-gnu
chmod +x open-ontologies-x86_64-unknown-linux-gnu && mv open-ontologies-x86_64-unknown-linux-gnu /usr/local/bin/open-ontologies
Docker:
docker pull ghcr.io/fabio-rovai/open-ontologies:latest
docker run -i ghcr.io/fabio-rovai/open-ontologies serve
From source (Rust 1.85+):
git clone https://github.com/fabio-rovai/open-ontologies.git
cd open-ontologies && cargo build --release
./target/release/open-ontologies init
Connect to your MCP client
<details> <summary><strong>Claude Code</strong></summary>Add to ~/.claude/settings.json:
{
"mcpServers": {
"open-ontologies": {
"command": "/path/to/open-ontologies/target/release/open-ontologies",
"args": ["serve"]
}
}
}
Restart Claude Code. The onto_* tools are now available.
Add to ~/Library/Application Support/Claude/claude_desktop_config.json:
{
"mcpServers": {
"open-ontologies": {
"command": "/path/to/open-ontologies/target/release/open-ontologies",
"args": ["serve"]
}
}
}
Add to .cursor/mcp.json or equivalent:
{
"mcpServers": {
"open-ontologies": {
"command": "/path/to/open-ontologies/target/release/open-ontologies",
"args": ["serve"]
}
}
}
{
"mcpServers": {
"open-ontologies": {
"command": "do