Open Ontologies

Judgement

What it is

Developer tool

What it does

A Rust binary and MCP server that plans, applies and rolls back changes to OWL ontologies, reports which classes each change affects, and produces Lean-checked proofs of derived facts.

Adopt it when

You maintain a production OWL or RDF ontology and need reviewable change plans and machine-checkable evidence for auditors.

Watch out

The project is about eight months old with a single main author and a niche audience, so expect change.

Ready for

Experimental

Runs as

Command line and self-hosted server

Built with

Rust, Python and Lean

How established

Young: started 8 months ago, latest release v2.1.0.

What the license allows

You can build it into a product you sell, as long as you keep its copyright notice.

Judged on 2026-11-06 from the project's README and GitHub data. The license and age lines are worked out directly.

Built from

Follow it down: Open Ontologies → Rust → runs on a microchip

How compilers were built, back to punched paper tape

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