API Changelog

List Calls Response Update

The GET /v2/calls endpoint now returns additional call metadata and pagination information to provide more comprehensive call details.

New Fields:

• pagination object with total_records, limit, and offset for paginated responses
• judge_results — Call quality judging results
• agents_used — Array of agents used during the call
• executed_actions — Actions executed during the call
• type_of_call — Call direction (inbound/outbound)
• error_message — Error details if call failed
• call_status — Current status of the call
• labels — Array of labels associated with the call
• agent_phone_number — Phone number used by the agent
• deployment_type — Type of deployment
• name — Name of the call recipient

Removed Fields:

• timeline, recording_sid, and voice_engine_type are no longer returned

New Webhook Logs Endpoints

We’ve added two endpoints to manage Webhook Logs programmatically.

Endpoints Added:

• GET /logs — List webhook logs
• GET /logs/:webhook_log_id — Retrieve a webhook log by ID

New Simulations Endpoints

We’ve added a comprehensive set of new endpoints to manage Simulation Cases and Simulation Sessions programmatically.

• Case Management: Create, list, retrieve, update, delete, and generate simulation cases.
• Session Management: Start a simulation and list/retrieve simulation sessions.
• Listings: List simulation cases by agent and list all simulations.

Endpoints Added:

• POST /simulations — Create a simulation case
• GET /simulations — List simulation cases
• GET /simulations/:case_id — Get a simulation case
• PUT /simulations/:case_id — Update a simulation case
• DELETE /simulations/:case_id — Delete a simulation case
• POST /simulations/generate — Generate simulation cases
• GET /simulations/agent/:agent_id — List simulation cases by agent
• POST /simulations/start — Start a simulation
• GET /sessions — List simulation sessions
• GET /sessions/:session_id — Get a simulation session
• GET /simulations/all — List simulation cases
• GET /simulations/:case_id — Get a simulation case

Read more about the feature here: https://docs.synthflow.ai/simulations

Subaccount Update: Import/Return Products

Added support to the update subaccount endpoint to manage importing objects like phone numbers from the parent workspace to subaccounts.

• New optional field operation_type (string): allowed values import, return.
• New optional field products.phone_numbers[].number to specify E.164 numbers to import to or return from the subaccount_id.

• PUT /subaccounts/:subaccount_id — Update a subaccount

New timeout value for custom actions

You can now specify a failure_timeout field when creating or updating a custom action. This allows you to control how long a custom action is allowed to run before it is automatically terminated if the timeout is reached.

Deprecated Language Value

The es language code is no longer supported. Please use es-ES for Spanish when creating or updating agents.

• POST /assistants/ — Create an agent
• PUT /assistants/:model_id/ — Update an agent

Phone books: new API endpoints

New endpoints added:

• POST /phonebooks/ (Create a phone book)
• GET /phonebooks/ (List phone books)
• DELETE /phonebooks/:phone_book_id/ (Delete a phone book)
• POST /phonebooks/:phone_book_id/entries/ (Create a phone book entry)
• DELETE /phonebooks/:phone_book_id/entries/:entry_id (Delete a phone book entry)

GPT-5 is now supported

Added GPT-5 support for agents.

• POST /assistants/ (Create an agent)
• PUT /assistants/:model_id/ (Update an agent)

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 "agent": {
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    "llm": "gpt-5-chat"
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  }

Contacts and Memory stores: new API endpoints

Contacts

New endpoints added:

• POST /contacts/ (Create a contact)
• GET /contacts/ (List contacts)
• GET /contacts/:contact_id/ (Get a contact)
• PATCH /contacts/:contact_id/ (Update a contact)
• DELETE /v2/contacts/:contact_id (Delete a contact)

Memory stores

New endpoints added:

• POST /memory_stores/ (Create a memory store)
• GET /memory_stores/ (List memory stores)
• PATCH /memory_stores/ (Update a memory store)
• DELETE /memory_stores/ (Delete a memory store)
• GET /memory_stores/:memory_store_id/ (Get memory stores by contact ID)
• POST /memory_stores/:memory_store_id/assistants/:assistant_id/attach/ (Attach a memory store to an agent)
• POST /memory_stores/:memory_store_id/assistants/:assistant_id/detach/ (Detach a memory store from an agent)
• POST /memory_stores/:memory_store_id/contacts/:contact_id/memory_data (Get data for a specific memory store and contact)
• POST /memory_stores/:memory_store_id/contacts/:contact_id/attach (Attach a contact to a memory store)
• POST /memory_stores/:memory_store_id/contacts/:contact_id/detach (Detach a contact from a memory store)

Call Transfer to SIP Documentation

We’ve added comprehensive documentation for the Call Transfer to SIP feature, enabling AI agents to seamlessly transfer calls to SIP endpoints and human agents.

Key Features Documented:

• Transfer Modes: Warm transfer with message, warm transfer with context summary, and blind transfer
• SIP Endpoint Support: Compatible with SIP phones, trunks, PBX systems, and cloud services
• Configuration Guide: Step-by-step setup instructions for Synthflow and SIP endpoints
• Advanced Configuration: Multiple transfer destinations, conditional transfers, and context sharing
• Testing and Troubleshooting: Comprehensive testing procedures and common issue resolution
• Best Practices: Security considerations, user experience optimization, and maintenance guidelines

Supported SIP URI Formats:

• Standard SIP URIs (sip:user@domain.com)
• SIP URIs with ports and transport protocols
• Phone numbers and extensions

This documentation provides everything needed to implement and maintain Call Transfer to SIP functionality in enterprise environments.