Skill development

A Strata19 skill should state when it applies, when it does not, prerequisites, public operations, human gates, recovery behavior, completion evidence, and the destination surface. It should teach a workflow a host can actually execute with the installed tool projection.

Reference exact strata19.* operations and action discriminators. Do not rely on an internal helper that the host cannot see. If a step can return unsupported, teach the caller how to read the typed reason instead of inventing a successful result.

Add the skill under plugins/strata19/skills/<skill-name>/SKILL.md, register it in the relevant plugin manifests, and test that named operations still match the projection registry. A version bump and reinstall are required before a running Codex session sees the change.