Rust MCP server for validating, querying, governing, and planning over RDF/OWL ontologies with an in-memory Oxigraph store.
Copy the AI prompt to install this server into Claude Code, Cursor, or another agent — or use 1-click editor setup below.
One-click editor setup isn’t available for this listing yet — we don’t have a confirmed install command, and we’d rather show nothing than point your editor at the wrong package or host. Follow the project’s own setup instructions, linked above.
Inspect callable tools, capabilities, and parameters exposed to AI agents by Open Ontologies.
A Terraforming MCP for Knowledge Graphs
Validate, classify, and govern AI-generated ontologies. Written in Rust. Ships as a single binary.
English · ç®€ä½“ä¸æ–‡
Quick Start · Studio · Benchmarks · IES · Tools · Extending · 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.
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.
| 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. |
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 — competency-question runner with pitfall hints + LLM-judgement loop.onto_classify_el — OWL-EL classification (transitive subsumption table, trivial pairs excluded).onto_eval_alignment — P/R/F1 over reference + computed alignment sets.onto_shape_combinatorics + onto_shape_induce — property-combination lattice + data-driven SHACL shape induction with support × confidence ranking.borderline_partition + borderline_record_verdict — generalised two-threshold review loop for any candidate set.onto_align_fuzzy — embedding-free fuzzy-logic adjudication with 10-rule Mamdani inference; HNSW is demoted to a candidate generator.onto_align_flora — end-to-end alignment pipeline pairing the signal extractor to the fuzzy adjudicator.onto_policy_register + onto_policy_list + onto_policy_check — authorisation gate that composes with onto_certify_action (Causal = risk; policy = authorisation).eval_rag + eval_rag_mmrag — Hit@k / MRR / faithfulness / token-Jaccard / ROUGE-1 scoring for retriever pipelines, with a dataset adapter.graph_projection_lossy_check — the auditor that pairs with onto_segment_retrieve.Walks Dynamics register → PDDL compile → Fast-Downward-shaped sas_plan parse → orchestrator-side IRI bind → sandbox validate → CIVeX certify → apply with OWL-RL ramification → final state inspection. Every layer through its public API, no external dependencies (Python, DoWhy, Fast Downward) required.
Zero new external Rust dependencies; everything optional gates behind Cargo features. Full test suite (160+ tests) green on default build; cargo clippy --lib --tests --examples -- -D warnings clean across both default and causal-pywhy configurations.
Pre-built binaries:
Docker:
servestarts an MCP server that speaks JSON-RPC over stdin/stdout — it is not an interactive CLI, so on launch it will appear to "hang" while it waits for an MCP client to connect. That is expected. To try the tools directly from a terminal instead, use the CLI subcommands (e.g.open-ontologies validate <file.ttl>); to use it with an LLM, wire it into an MCP client as shown under Connect to your MCP client.
From source (Rust 1.85+):
For native Windows builds, see docs/windows.md.
Add to ~/.claude/settings.json:
Restart Claude Code. The onto_* tools are now available.
Add to ~/Library/Application Support/Claude/claude_desktop_config.json:
Add to .cursor/mcp.json or equivalent:
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