Open Ontologies

Overview

Open Ontologies is a Rust engine for production ontology change management. It plans and applies changes with a blast radius report, reasons over OWL and RDFS, and produces derivation certificates that a separate Lean 4 checker can verify. Tesseract Semantics describes a hosted platform built on the engine and positions it for enterprise data interoperability.

Key Features

• Change management for production ontologies: plan, blast radius, risk score, locked IRIs, apply, monitor, drift, and rollback.
• Reason over OWL and RDFS, producing materialised inferences and a derivation certificate accepted by a proved Lean 4 checker.
• Validate against SHACL with a reported measurement against the W3C suite.
• Evaluate SWRL, RIF Core, or Horn rules and return a verdict word that distinguishes supplied rules from standard rules.
• Load CSV, JSON, XML, YAML, XLSX, Parquet, PostgreSQL, and DuckDB into RDF.
• Provide an MCP server so Claude or Cursor can operate the engine in conversation.

Use Cases

• Reviewing the consequences of an ontology change before it reaches production.
• Giving auditors or reviewers a certificate they can re-check independently.
• Preparing ontology slices for RAG while tracking entailment preservation per claim.
• Checking ontology satisfiability or inconsistency and validating data against SHACL.

Getting Started

• Build the Lean checkers from the lean directory with lake build; the build uses core Lean 4 and no Mathlib.
• Run lake exe oo-horn check with built-in rules, asserted triples, and a conclusion file to verify entailment or refusal.
• Load a TTL file with open-ontologies --data-dir /tmp/oo-demo/store load coffee.ttl, then reason with --profile rdfs --certificate ./cert.
• Re-check a certificate with lake exe oo-cert asserted.tsv derivations.tsv.

Deployment & Requirements

• Runs entirely in your own environment; data never leaves the organisation.
• Ships as one binary and does not require a JVM or Protégé.
• The Lean checker builds with core Lean 4 and no Mathlib.
• A container image is available from GHCR.

Before You Adopt

• License: MIT. Review its terms before using, modifying, or distributing the project.
• The no-cost evaluation is time-limited and capped at ten enterprise teams.
• The tool is not an ontology editor; class hierarchy drawing is left to Protégé.