open-ontologies

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

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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 32 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.

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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