Ontologian
A Claude Code plugin for structured knowledge management based on Palantir Ontology concepts.
Ontologian brings Object Types, Link Types, and Action Types into your Claude Code workflow — letting you define, navigate, and validate your domain knowledge as structured YAML directly inside your project.
Installation
Step 1 — Register the marketplace
curl -fsSL https://raw.githubusercontent.com/swszz/ontologian/main/setup.sh | bash
Adds Ontologian's GitHub repo as a known marketplace source in ~/.claude/settings.json.
Requires: jq or python3.
Step 2 — Install commands & agent
Run inside Claude Code:
/plugin install ontologian@ontologian
Installs 8 slash commands (/ontologian, /ontologian-add, /ontologian-analyze, /ontologian-consult, /ontologian-search, /ontologian-validate, /ontologian-sync, /ontologian-visualize) and the ontology-consultant proactive agent.
Update
/plugin update ontologian@ontologian
No need to re-run setup.sh — this updates commands and agent only.
Commands
| Command | Description |
|---|
/ontologian-consult | Start a Palantir-grade ontology consulting session — guided discovery, design, construction, and governance documentation |
/ontologian | Show domain list and status summary |
/ontologian-add | Interactively add a new type to a domain |
/ontologian-analyze | Derive ontology structure from free-form requirements |
/ontologian-search <keyword> | Search across all domains (use --type object|link|action and --domain <name> to filter) |
/ontologian-validate | Check YAML schema and referential integrity |
/ontologian-sync | Sync local .ontology/ to the global store |
/ontologian-visualize | Render an ASCII relationship diagram |
Consulting Agent
The plugin includes an ontology-consultant agent that activates in two ways:
- Proactively — when you describe business requirements, system design, or domain entities, the agent automatically offers to model them as an ontology
- Explicitly — run
/ontologian-consult to start a full consulting session immediately
The consulting session covers 6 phases:
| Phase | What happens |
|---|
| Phase 0 — Scope | Confirm the domain scope and whether to start from existing requirements or a blank slate |
| Discovery | 5-axis structured interview: entities, relationships, processes, boundaries, governance |
| Modeling | Autonomous candidate derivation using the same rules as /ontologian-analyze |
| Design | Palantir enrichment patterns: object enrichment, state machine audit, semantic naming review, governance metadata |
| Construction | Writes all domain files in dependency order, runs automatic validation |
| Delivery | Renders ASCII diagrams for all domains, generates .ontology/CONSULT_REPORT.md |
Examples
/ontologian-consult
"We run a logistics platform. Shipments are assigned to Drivers, pass through Hubs, and each leg is tracked as a RouteSegment."
/ontologian-analyze
"Users sign up and place Orders. Each Order has multiple OrderItems linked to a Product. When an Order is confirmed, we send a confirmation email."
/ontologian-add
"Add a new Object Type called Invoice to the billing domain — has invoice_id, issued_at, total_amount, and status (draft, sent, paid, overdue)."
/ontologian-search order --type action
/ontologian-validate
/ontologian-visualize
/ontologian-sync
Plugin Structure
ontologian/
├── .claude-plugin/
│ └── marketplace.json # Marketplace manifest (repo root only)
├── plugin/ # Plugin content (installed via git-subdir)
│ ├── .claude-plugin/
│ │ └── plugin.json
│ ├── skills/ # One directory per skill
│ │ ├── add/SKILL.md
│ │ ├── analyze/SKILL.md
│ │ ├── consult/SKILL.md
│ │ ├── search/SKILL.md
│ │ ├── status/SKILL.md
│ │ ├── sync/SKILL.md
│ │ ├── validate/SKILL.md
│ │ └── visualize/SKILL.md
│ ├── agents/
│ │ └── ontology-consultant.md
│ └── hooks/
│ ├── hooks.json
│ └── session-start
├── setup.sh # Marketplace registration script
└── README.md
Architecture: marketplace.json lives at the repo root. The plugin is installed from the plugin/ subdirectory. Each skill is self-contained in its own skills/<name>/SKILL.md directory.
How It Works
The .ontology/ directory is created lazily — it does not exist until you run your first write command (/ontologian-add or /ontologian-analyze). Read-only commands (/ontologian, /ontologian-validate, /ontologian-search) require the directory to already exist.
When first created, the directory structure looks like this:
