Prepare the handoff
Identify the number owner, call direction, target workspace and agent, and the existing route that should remain active. Keep a record of the provider-side call identifier without including credentials.1
Review the future request boundary
The declared request includes agent, caller, destination, direction, and optional conversation initiation data. Validate these against the selected workspace and version rather than trusting caller-supplied values.
2
Separate the two HTTP contracts
Twilio’s webhook contract and the Threetone registration request are not interchangeable merely because both concern a call. A released integration must document request authentication, field mapping, and the exact response.
3
Specify failure behavior
Decide what the caller hears if registration fails, how the existing route is preserved, and who owns termination. Avoid retrying a non-idempotent registration without checking whether a session was created.
4
Require release evidence
Before changing carrier configuration, require a supported handler, documented webhook credential handoff, usable call instructions, and a successful authorized test of answer, audio, and hangup.
Failure handling
Treat the current 501 response as an implementation boundary. Rotating credentials or retrying it cannot enable the handler. Route support questions with the operation name and response status, keeping secrets and full caller details out of the report.Frequently asked questions
Does number import enable registration?
Does number import enable registration?
No. Import saves a phone record. Registration remains unimplemented.
Can I use registration to place a new outbound call?
Can I use registration to place a new outbound call?
No. Outbound initiation is a separate operation with its own provider and runtime gates. See Twilio native integration.