assistant.group-binding.start

Only caller.kind=product. Product comes exclusively from registered caller; product_id is forbidden in requests. Require both ai-service and whatsapp-channel for the project; either missing returns PERM.ENTITLEMENT_MISSING (403). Reserve two numbers for ten minutes with generated group_binding_id as Messaging Idempotency-Key. A new start creates a new binding. Numbers are private display values, never routing keys. Return code only here with Cache-Control: no-store; persist only a binding-salted hash.

POST /internal/assistant/v1/group-bindings/start