本体知识图谱编辑器

Setup (Playwright / headless)

navigator.modelContext does not exist in headless Chromium. Inject the polyfill before the page loads using page.addInitScript:

await page.addInitScript(() => {
  const tools = {};
  Object.defineProperty(navigator, 'modelContext', {
    value: { registerTool: async (n, _d, _s, h) => { tools[n] = h; } },
    configurable: true,
  });
  window.__mcpTools = tools;
});

// After page load:
await page.evaluate(async () => {
  const mod = await import('/src/mcp/ontosphereMcpServer.ts');
  await mod.registerMcpTools();
});

// Call a tool:
await page.evaluate(async ([name, params]) => window.__mcpTools[name](params),
  ['addNode', { iri: 'ex:alice', typeIri: 'foaf:Person', label: 'Alice' }]);

In a browser with native navigator.modelContext, tools register automatically on app load.

Quick start (development)

1. Install dependencies:

   npm install
   

   npm run dev
   

   http://localhost:8080/
   

Full example (CKAN private dataset via Fuseki SPARQL)

http://docker-dev.iwm.fraunhofer.de:8080/
  ?rdfUrl=https://docker-dev.iwm.fraunhofer.de/dataset/<uuid>/fuseki/$/sparql
  &apiKey=<ckan-api-jwt-token>

Example output

An AI agent built this from scratch in one session — full demo with tool calls →

Reasoning demo

The reasoning demo showcases OWL 2 DL / SROIQ(D) inference on a small employee ontology: Open demo ↗

The demo (public/reasoning-demo.ttl) defines a Person → Employee → Manager → Executive hierarchy with ABox assertions that drive inference patterns across all OWL 2 DL construct groups:

OWL 1 RL patterns: 1. rdfs:subPropertyOf — ex:hasFriend sub-property of ex:knows: alice hasFriend bob → alice knows bob. 2. owl:inverseOf — ex:isManagedBy inverse of ex:manages: alice manages carol → carol isManagedBy alice. 3. owl:SymmetricProperty — ex:isColleagueOf is symmetric: bob isColleagueOf carol → reverse direction. 4. owl:TransitiveProperty — ex:hasSupervisor is transitive: bob→alice, alice→dave → bob→dave. 5. rdfs:domain — ex:dave has no type; because he is subject of ex:manages (domain ex:Manager), the reasoner infers dave rdf:type ex:Manager.

OWL 2 DL extensions: 6. owl:someValuesFrom — alice and carol each worksOn projectAlpha (a Project) → inferred ProjectContributor. 7. owl:hasValue — carol isManagedBy alice (via inverseOf) → carol inferred DirectReport (hasValue restriction on alice). 8. owl:intersectionOf — dave manages bob (inferred Manager) and eve (Employee) → dave inferred TeamLead. 9. owl:disjointWith — Contractor disjointWith Employee; frank is a Contractor (structural TBox constraint). 10. owl:complementOf — NonEmployee ≡ ¬Employee (structural TBox only). 11. owl:propertyChainAxiom — hasGrandManager ← hasSupervisor ∘ hasSupervisor: carol→bob→alice → carol hasGrandManager alice. 12. owl:unionOf — LeadershipTeam ≡ Executive ∪ Manager: alice (Executive) and dave (inferred Manager) → inferred LeadershipTeam. 13. owl:sameAs — aliceCEO sameAs alice: aliceCEO inherits all of alice's inferred types including Executive.

A separate inconsistency demo (public/reasoning-demo-inconsistent.ttl) shows the consistency checker in action: Open inconsistency demo ↗

inc:frank is asserted as both inc:Employee and inc:Contractor, which are declared owl:disjointWith. Running reasoning produces isConsistent: false, reasoning is skipped, and the report's Errors tab shows the disjointness clash on frank.

Demo

Regenerate:

```sh npm run demo:all

Recording demo videos

See docs/demo-scripts/HOWTO.md for the full guide.

Two styles of demo video are supported:

Seed-driven — write a seed markdown file in docs/mcp-demo/seeds/ with JSON-RPC tool calls embedded in backtick blocks. The runner parses the seed and executes each turn directly against window.__mcpTools. Existing seeds: foaf-social-network, reasoning-demo, scene-ontology, pizza-tutorial.

Chat-style (side-by-side) — open demo-stage.html (mock chat left, app right), inject messages programmatically via addChatMessage(), and call tools on the app iframe via callToolOnStage(). No relay popup needed. Example: pizza-tutorial-chat.

Demo videos

To re-record all videos:

npm run demo:video   # starts dev server, records, encodes, kills server

Authentication (API key)

?rdfUrl=https://private-endpoint.example.org/data.ttl
&apiKey=Bearer+my-token
&apiKeyHeader=Authorization

The API key is sent only with the RDF fetch request. CORS: the server must allow the Ontosphere origin with credentials (wildcard * origins are incompatible with authenticated requests).

AI / MCP Integration

Ontosphere exposes a full Model Context Protocol tool surface so AI agents can build and reason over knowledge graphs through natural-language chat.

Recommended workflow

loadOntology (TBox)
  → addNode ×N  (ABox individuals, rdf:type set)
  → addLink ×N  (object-property triples, edges appear on canvas)
  → runLayout   (dagre-lr recommended)
  → expandNode  (reveal annotation property cards — omit iri to expand all)
  → runReasoning (infer subClass / domain / range entailments; isConsistent=false signals contradiction)
  → fitCanvas + exportImage   (SVG snapshot, token-efficient)
  → exportGraph(turtle)       (final deliverable)

Troubleshooting

• rdfUrl doesn't load on open:
• Confirm the URL is percent-encoded in the address bar.
• Open DevTools → Network and check the fetch request and response headers.
• Look for CORS errors (Access-Control-Allow-Origin).
• Check the console for RDF parser errors or application diagnostics.
• 403 when using certain query parameter names:
• Some servers intercept reserved query names. Use ?rdfUrl=... to avoid conflicts.
• Graph is very large / slow:
• Increase the large-graph threshold in Settings or reduce the number of loaded triples.
• Clustering activates automatically above the threshold; use Expand All sparingly on huge graphs.