Schema Unification (gbrain-base → gbrain-base-v2)

v0.41.22 ships gbrain-base-v2 — a 15-type DRY/MECE taxonomy (14 canonical + note catch-all) — as the install default for new brains. Existing brains on gbrain-base can opt in via the pack_upgrade_available onboard finding + the unify-types PROTECTED Minion handler.

This skill is the playbook for that migration.

brain_first: exempt

This skill is ABOUT the brain's shape — it can't depend on the brain it's reshaping. No gbrain search lookup first; jump straight to onboard.

When this skill fires

• Agent runs gbrain onboard --check and sees pack_upgrade_available or type_proliferation warnings
• User asks "what is the canonical taxonomy / how do I clean up my page types / migrate to v2"
• A dangling_aliases finding surfaces (post-unify GC)
• An agent ingesting from a custom pack wants to consult the v2 taxonomy as a reference

Mental model (one paragraph)