The Tonto ontology skill packages the same modeling knowledge in a skill-oriented format for agentic tools. It is useful when the assistant supports task routing through a SKILL.md file and can load detailed reference files only when needed.
Guidance files are broad project instructions. Skills are task-oriented references. They can be installed together.
Add the skill with the CLI
Run the command from a Tonto project:
tonto-cli add-skill . --target codex
tonto-cli add-skill . --target all
Supported target values are:
cursor
vscode
codex
claude
google
all
If --target is omitted, the CLI asks which editor or agentic IDE you use.
Add the skill from VS Code
Open the project folder in VS Code and run:
Tonto: Add Tonto Skill to project
Generated locations
| Target | Skill location |
|---|---|
| Cursor | .cursor/skills/tonto-ontology/ |
| VS Code / GitHub Copilot | .github/skills/tonto-ontology/ |
| Codex | .codex/skills/tonto-ontology/ |
| Claude Code | .claude/skills/tonto-ontology/ |
| Google Gemini / Antigravity | .agents/skills/tonto-ontology/ |
| All | Every target above |
Skill contents
The skill contains:
| File | Role |
|---|---|
SKILL.md | Main entry point with Tonto syntax, OntoUML stereotypes, relation syntax, project conventions, and task routing. |
references/extending.md | Detailed workflow for adding classes, attributes, relations, generalization sets, and packages. |
references/terminology.md | Naming and terminology analysis criteria. |
references/summarization.md | Summarization structure for packages and complete ontologies. |
references/documentation.md | Documentation rules for labels, descriptions, and explanatory comments. |
Guidance files vs skills
| Use case | Prefer |
|---|---|
| Cursor rules, Copilot instructions, and always-available repository context | Guidance files |
| Agent tools that discover task skills and load references on demand | Tonto ontology skill |
| A project where multiple assistants may be used | Both |
| A lightweight setup for only one modeling session | Guidance files |
| Reusable Tonto modeling knowledge shared across projects | Skill |
Skill routing
The skill routes common requests to specialized references:
- Creating or extending the ontology ->
references/extending.md - Improving names, terminology, or consistency ->
references/terminology.md - Explaining or summarizing an ontology ->
references/summarization.md - Writing labels, descriptions, or JSDoc comments ->
references/documentation.md
The routing matters because Tonto tasks mix syntax with ontological judgment. For example, creating a Student class is not only a code-generation step; the assistant must decide whether it is a role, phase, subkind, or another UFO category based on the domain.
Recommended use
When using a skill-enabled assistant, start requests with the intended task:
Use the Tonto ontology skill. Analyze the terminology of this ontology,
especially class stereotypes and relation names. Do not edit files yet;
return findings and suggested fixes first.
For edit requests:
Use the Tonto ontology skill to extend this project with publication venues.
Inspect all imports and existing packages first, then edit the smallest set of files.
Explain the stereotype rationale for every new class.
After accepting changes, validate the model:
tonto-cli validate .