Work with skills

This guide covers the lifecycle of a Skill: loading a built-in one, switching between them, extending one as your domain reveals edge cases, and composing several onto a single ontology. A Skill targets an ontology and gives Jax capabilities — a system prompt, tool bindings, validators, and toggles. You need a project with an ontology in place.

Most teams start by loading a built-in Skill, doing real work, then extending it when the defaults do not cover something. The ontology stays fixed; Skills are the swappable layer on top.

Steps

1. Load a built-in Skill. When you create a project, pick a starting Skill from the catalog (FTTH network design, water operations, and so on). It becomes your project's local copy, free to edit. Built-in updates do not overwrite your changes unless you opt in.

1. Switch Skills from the project header. A project binds one ontology and any number of Skills, and you can change which Skill is active without touching your data. Use the Skills swap dialog in the header; the new Skill must target the project's ontology.

1. Extend a Skill by adding a property or constraint. The most common change is teaching the Skill about a field the default missed. The easiest path is to ask Jax — it makes the change, validates it, and tells you what migrated.

Add a splice_type field to closures. Allowed values mechanical, fusion, rotary. Default fusion.

1. Add a constraint and watch it propagate. Constraints are first-class. Once added, the validator surfaces violations on the Globe, Jax respects the rule on its next run, and reports include it by name.

Add a constraint: any cabinet must be within 250 m of a road.

1. Compose Skills onto one ontology. For projects that span concerns — a municipal project with both fiber and street lighting — load both Skills against the shared ontology. Entity types stay namespaced; shared concepts like a road or a building collapse to one layer used by both.

1. Draft a new Skill when the catalog falls short. Describe the capability to Jax in natural language; it drafts the prompt, tool bindings, and validators. Review the diff, edit, and save. Expect to iterate — the first draft is rarely the final.

Draft a permit-intelligence Skill that flags any design crossing a parcel boundary that lacks an easement.

Tips

• Keep the ontology and the Skill separate in your head: the ontology says what exists, the Skill says what Jax does about it.
• Skills are versioned per project — you can roll back, branch, or compare revisions, so extend freely.
• When composing, load the smallest set of Skills that covers the work; more Skills means more for Jax to weigh on each run.
• If a change feels structural (a whole new entity type), it belongs in the ontology, not the Skill.

Where to go next

• Define the types your Skills target in Build an ontology.
• Put a loaded Skill to work in Designing with Jax.
• Browse what ships out of the box in Skills overview.