open-ontologies vs orionbelt-ontology-builder
Rust MCP server + desktop Studio for AI-native ontology engineering: 70+ tools over an in-memory Oxigraph store — OWL2-DL tableaux reasoning, SHACL, SPARQL, versioning. Single binary, no JVM. — versus — Browser ontology workbench for OWL and SKOS on Streamlit + rdflib: OWL-RL reasoning, 22 SKOS checks, SPARQL console, bulk edits, gist starters and a vis-network graph — no Java, no Protégé.
Both are ontology workbenches with reasoning and validation. Open Ontologies is agent-first — a Rust MCP server with 70+ tools over Oxigraph plus a desktop Studio; OrionBelt is human-first, a Streamlit app over rdflib with undo, diffs and bulk edits.
| open-ontologies | orionbelt-ontology-builder | |
|---|---|---|
| Stars | 1.1k | 216 |
| Forks | 144 | 22 |
| Language | Rust | Python |
| License | MIT | BUSL-1.1 |
| Last activity | 2 days ago | 5 days ago |
| Topics | knowledge-graphs | knowledge-graphs |
| Curated connections | 11 | 3 |
open-ontologies — the curator's take
Protégé for the agent era, with the right division of labor: the server validates, reasons and scaffolds; the LLM connected over MCP does the intelligence — no internal API keys. A DL tableaux reasoner in a single binary is legitimately rare. When NOT: ★315 with an enormous surface (70+ tools, Studio, planner, causal layer) on one maintainer's velocity — expect edges to move; if you only need graph retrieval, this is over-engineering.
orionbelt-ontology-builder — the curator's take
For the ontology work that a knowledge-graph project actually needs — classes, properties, SKOS vocabularies, cleanup — without installing Protégé: pip install, open the browser, and every change is an undo checkpoint, every delete shows what breaks first, every import shows a diff. Validation names the orphan classes, duplicate labels and broader/narrower cycles with locations. Human-first, deliberately lighter than Protégé. NOT an agent-facing tool (no MCP, no API — Streamlit is the interface), NOT for pure RDFS vocabularies like schema.org (they don't surface in the panels). Licence is BUSL-1.1: free for any use including production, but you may not embed it in a commercial product or service until it converts to Apache-2.0 on 2030-03-30.