May 28, 2026 | Synthflow

Agents API: STT provider and speech recognition

Create and update assistant requests now accept the speech-to-text fields from the assistant editor.

Endpoint	Change
POST /assistants, PUT /assistants/{model_id}	`agent.transcriber_provider` (`deepgram`, `deepgram-nova-3`, `synthflow-stt`) and `agent.transcriber_speech_recognition` (`faster`, `high_accuracy`).

Call Transfer API: Human availability

Configure transfer office hours on LIVE_TRANSFER actions through create and update requests.

Endpoint	Change
POST /v2/actions	`human_availability` (`timezone`, `schedule`, `unavailable_message`, `active`).
PUT /v2/actions/{action_id}	Same `human_availability` fields on update.

Agents and Actions API: Action-assistant assignment relationships

Assistant and action detail endpoints accept optional query parameters to include related IDs. Relationship fields stay empty by default.

Endpoint	Query parameter	Response field
GET /assistants/{model_id}	`include_actions`	`actions` (action IDs)
GET /actions/{action_id}	`include_assistants`	`assistants` (assistant IDs)

Actions API: Input variable mapping

Configure how each input variable is collected per assistant attachment, so one shared action can use different variable sources on different agents. Action placeholders and mapping explains the mapping options in the product UI.

Endpoint	Change
POST /actions/attach	Batch `items` payloads with `input_variables_mapping` per attachment. Legacy `model_id` + `actions` format still supported.
GET /actions/{action_id}	`input_variables.values` and `input_variables.assistants[]` with per-assistant mapping details.