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  1. Home
  2. 🧠 Knowledge & Memory
  3. Open Ontologies
Open Ontologies logo
Health: ActiveRecent health check succeeded.Last checked 9/9/2026, 12:02:18 PM

Open Ontologies

User RatingsBe the first to rate and review this MCP server!
View Repository488 GitHub StarsTotal stargazers on GitHub for the source repository (488 stars).Visit Website
ontologiesknowledge-graphsrdfowlshacl

Rust MCP server for validating, querying, governing, and planning over RDF/OWL ontologies with an in-memory Oxigraph store.

Quick Install

Automated & IDE Setup

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.

Manual Client & Custom JSON ConfigExpand JSON â–¾
No confirmed setup config for this listing yet. We only publish a config block when the install details come from the project itself — its README, its docs, or a verified owner. We haven’t found those for fabio-rovai/open-ontologies, and we’d rather show nothing than a guess you’d paste into your client. Follow the project’s own setup instructions for the current steps.
Install Directory Badge Claim listing Alternatives🧠 More in Knowledge & Memory

Overview

Open Ontologies provides MCP tools for ontology engineering across RDF, OWL, SHACL, and SPARQL workflows. It supports validation, querying, diffing, linting, versioning, alignment, reasoning, planning, certification, and governance in an in-memory Oxigraph triple store. A desktop Studio provides visual ontology navigation, AI chat, property inspection, and lineage views.

Use cases

•Validate OWL ontologies and SHACL constraints
•Query RDF knowledge graphs with SPARQL
•Compare, version, and audit ontology changes
•Compile and validate classical plans from ontology actions
•Align schemas and evaluate candidate mappings

Key features

•RDF/OWL ontology validation and reasoning
•SPARQL querying with an in-memory Oxigraph store
•SHACL validation and incremental co-evolution checks
•Ontology alignment, classification, and structured extraction
•Action registration, causal certification, and policy checks
•Planning compilation, simulation, and validation

Capabilities & Tool Schemas

Inspect callable tools, capabilities, and parameters exposed to AI agents by Open Ontologies.

Extracted Tool Capabilities
RDF/OWL ontology validation and reasoning
SPARQL querying with an in-memory Oxigraph store
SHACL validation and incremental co-evolution checks
Ontology alignment, classification, and structured extraction
Action registration, causal certification, and policy checks
Planning compilation, simulation, and validation

Documentation Overview

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.

Stars Forks CI MIT Container image on GHCR Obsidian plugin PitchHut ClawHub Sponsor

English · 简体中文

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.


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

LayerWhat it ships
DynamicsActionSchema + 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.
Causalonto_certify_action with optional PyWhy backdoor identification (opt-in via causal-pywhy feature). Structural-proxy default + do-calculus opt-in + graceful fallback.
Planneronto_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 — 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.

Validating end-to-end

bash
cargo run --example three_layer_pipeline

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.


Quick Start (MCP / CLI)

Install

Pre-built binaries:

bash
# macOS (Apple Silicon)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-aarch64-apple-darwin
chmod +x open-ontologies-aarch64-apple-darwin && mv open-ontologies-aarch64-apple-darwin /usr/local/bin/open-ontologies

# macOS (Intel)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-x86_64-apple-darwin
chmod +x open-ontologies-x86_64-apple-darwin && mv open-ontologies-x86_64-apple-darwin /usr/local/bin/open-ontologies

# Linux (x86_64)
curl -LO https://github.com/fabio-rovai/open-ontologies/releases/latest/download/open-ontologies-x86_64-unknown-linux-gnu
chmod +x open-ontologies-x86_64-unknown-linux-gnu && mv open-ontologies-x86_64-unknown-linux-gnu /usr/local/bin/open-ontologies

Docker:

Terminal
docker pull ghcr.io/fabio-rovai/open-ontologies:latest
docker run -i ghcr.io/fabio-rovai/open-ontologies serve

serve starts 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+):

bash
git clone https://github.com/fabio-rovai/open-ontologies.git
cd open-ontologies && cargo build --release
./target/release/open-ontologies init

For native Windows builds, see docs/windows.md.

Connect to your MCP client

Claude Code

Add to ~/.claude/settings.json:

config.json
{
  "mcpServers": {
    "open-ontologies": {
      "command": "/path/to/open-ontologies/target/release/open-ontologies",
      "args": ["serve"]
    }
  }
}

Restart Claude Code. The onto_* tools are now available.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

config.json
{
  "mcpServers": {
    "open-ontologies": {
      "command": "/path/to/open-ontologies/target/release/open-ontologies",
      "args": ["serve"]
    }
  }
}
Cursor / Windsurf / any MCP-compatible IDE

Add to .cursor/mcp.json or equivalent:

config.json
{
  "mcpServers": {
    "open-ontologies": {
      "command": "/path/to/open-ontologies/target/release/open-ontologies",
      "args": ["serve"]
    }
  }
}
Docker
config.json
{
  "mcpServers": {
    "open-ontologies": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "ghcr.io/fabio-rovai/open-ontologies", "serve"]
    }
  }
}
Obsidian

Read the full README →View source on GitHub →

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Adoption & maintenance

Factual signals from GitHub, npm, and our automated checks — not a rating.

GitHub stars
488
Stargazers on the source repository.
Last commit
5d ago
Most recent push to the default branch.
Directory activity
2 views
Config copies, upvotes, and views on AllMCPs.

Reviews

No reviews yet — be the first to share how this listing worked for you.

Frequently Asked Questions about Open Ontologies

It works with RDF and OWL ontologies, SHACL validation, and SPARQL queries.

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Technical Specs & Signals

Category🧠Knowledge & Memory
PricingFree
More technical detailsExpand â–¾
AuthNo auth required
LicenseMIT
Last updatedSep 5, 2026
Views2
Unique ViewsTotal visits recorded for this listing page on AllMCPs.
Installs0
Installs & Copy ActionsTotal times users copied install commands or configuration snippets for this server.
GitHub stars488
GitHub Star CountTotal stargazers on GitHub representing community popularity (488 stars).
Last commit5d ago
Last Repository CommitThe most recent commit or push recorded for this server's GitHub repository.Last commit on Sep 5, 2026
51Quality signal: Good · 51/100How this signal is calculated ▾
Server availabilityNot measured

Not scored for repo-hosted servers — we can't reach the running server, only its GitHub page. Hosted MCP endpoints are health-checked live.

Verified ownership10/20
Documentation & tools19/30
Adoption & activity9/15
Community engagement0/10

A guidance signal from public completeness & health data — not a user rating. New listings start lower and rise as they add docs, get verified, and grow adoption. Signals we can't observe for a listing are skipped, not counted against it.

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