Open Ontologies
A Terraforming MCP for Knowledge Graphs
Validate, classify, and govern AI-generated ontologies. Written in Rust. Ships as a single binary.
Quick Start · Studio · Benchmarks · IES · Tools · Architecture · Docs
Open Ontologies is a Rust MCP server and desktop Studio for AI-native ontology engineering. It exposes 70+ tools that let Claude build, validate, query, diff, lint, version, reason over, align, plan, certify, and govern RDF/OWL ontologies using an in-memory Oxigraph triple store — with a full three-layer Dynamics → Causal → Planner architecture, a marketplace of 33 standard ontologies, clinical crosswalks, semantic embeddings, and a full lineage audit trail.
The Studio wraps the engine in a visual desktop environment: virtualized ontology tree with hierarchy lines, breadcrumb navigation, and connection explorer; AI chat panel with /build (IES-level deep) and /sketch (quick prototype) commands; Protégé-style property inspector; and lineage viewer.
No JVM. No Protégé.
What's New (three-layer architecture + 13 new primitives)
The full Dynamics → Causal → Planner stack plus 13 new primitives. Every piece holds the MCP-native convention: the server provides validation and scaffolding, the connected LLM (Claude over MCP) does the intelligence. No internal LLM clients, no API keys, no provider abstractions.
Three-layer architecture
| Layer | What it ships |
|---|---|
| Dynamics | ActionSchema + 4 MCP tools: onto_action_register / _applicable / _apply / _list. Concurrent atomic ticks, static causal laws (invariants), default-value laws, ramification via OWL-RL closure, non-deterministic outcomes with reproducible seed. |
| Causal | onto_certify_action with optional PyWhy backdoor identification (opt-in via causal-pywhy feature). Structural-proxy default + do-calculus opt-in + graceful fallback. |
| Planner | onto_plan_compile_pddl + onto_plan_classical (Fast Downward subprocess) + onto_plan_validate (sandbox-simulate). Solver stays client-side; server compiles + validates. |
13 new primitives
onto_owl_shacl_coevolve_check+onto_owl_shacl_coevolve_incremental— SHACL validation against the OWL-RL closure, with dependency-graph routing so only shapes touching changed IRIs revalidate.onto_segment_retrieve— TBox-slice retrieval for ontology-grounded RAG.onto_extract_scaffold+onto_extract_validate— schema-guided structured extraction with typed datatype validation + conformance scoring.onto_cq_run+onto_verify_cq+onto_cq_verdicts_list— co