Open Ontologies is extensible on four surfaces, in increasing order of coupling:
| Surface | What it is | Contribute via |
|---|---|---|
| Community packs | Ontology data packs, installable through onto_marketplace at runtime |
PR to community/registry.json — see community/README.md |
| Community skills | Markdown workflow recipes that teach agents to chain onto_* tools |
PR to skills/community/ |
| Companion servers | Independent MCP servers composing with the core in one session | Follow the companion contract, then PR a row below |
| WASM plugins | Community onto_*-adjacent tools running in-process, sandboxed |
See docs/plugins.md |
| Name | What it does | Contract surface |
|---|---|---|
| OpenCheir | Workflow governance — enforcer rules over ontology-engineering sessions (validate-after-save, version-before-push), automatic verdict logging | Lineage webhook consumer (GOVERNANCE_WEBHOOK) |
| Name | What it does |
|---|---|
| Studio | Desktop app (Tauri) wrapping the engine — ontology tree, AI chat panel, property inspector, lineage viewer |
| Obsidian plugin | Brings the engine to Obsidian vaults — notes as a knowledge-graph surface |
The live registry is community/registry.json; onto_marketplace list shows the current set with "source": "community".
- Packs and skills: merged PR = listed, no separate step.
- Companion servers: PR a row to the table above; criteria in docs/companion-servers.md.