Provision (or resume provisioning) the hosted phone system for a business: carrier account, owner seat, Kai as extension 700, team ring group with the owner mobile, and the ring-team-then-Kai dial plan. Idempotent — a re-run resumes from stored ids. Pass business_address to save the street address first when the last attempt returned 409 missing_address. Owner role (session) or numbers:write. The admin key may also pass action=register_platform_webhook to register the per-environment events endpoint once (returns the signing secret exactly once).

get_flow reads the reconciled phone flow (who rings, for how long, business-hours mode) from the phone system; save_flow validates and applies a flow idempotently (loop guard on every member, schedule derived from business hours); propose_flow turns free text into a validated flow plus a one-sentence readback without applying it.

propose_flow: how the phones should ring, in the owner's words (e.g. "me and Maria ring for 20 seconds, after hours straight to Kai").

E.164 override for the ring-group member (defaults to the owner mobile on file).

add_ring_group_member: the teammate cell (E.164) to add to the team ring group. Owners/admins are also registered on the admin roster so calling the business line from that cell reaches the secretary. The forwarded-from office line is refused (loop guard).

add_ring_group_member: display name.

add_ring_group_member: member only rings; owner/admin can call Kai.