The phone lines this agent may work (F10.1)

GET 
/api/calls/lines

The call centre's channel sub-menu and the keypad's line picker.

GET /api/channels cannot serve this: it is gated by channels.manage, an ADMINISTRATIVE permission held by the people who connect a trunk rather than the people who answer it. A call-centre agent holds conversations.reply and nothing else, so reading the menu from there gave them a 403, an empty line list and a dead keypad — the phone worked and the panel said there was no phone.

The gate here is the DIALLER's own (conversations.reply plus the channel access rule), so a line offered here is exactly a line POST /api/calls/dial will accept. A menu more generous than the dialler is a security hole with a UI in front of it; a menu stricter than it is a menu that lies.

can_dial and address_kind are answered here rather than inferred by the client. A client that restates the capability contract drifts, and always toward drawing a button that cannot work.

No secrets: this is a phone book, not a keyring.

Responses

200

The lines, telephone providers first.

401

Not authenticated. code: account_disabled means the member's seat was deactivated in this workspace: the session is over even though the token was not revoked (clients sign out and clean up).

403

The actor may not reach a customer at all.