Changelog

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This changelog provides granular, real-time updates as changes are released. For a monthly summary of platform changes, see the Synthflow product changelog on our feedback portal.

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January 6, 2026

GPT-5.2 is now supported

Added GPT-5.2 support for agents.

EndpointTitle
POST /assistantsCreate an agent
PUT /assistants/:model_idUpdate an agent
1"agent": {
2   "llm": "gpt-5.2"
3 }

New parameter: message_before_action_starts for custom actions

Custom actions now support an optional message_before_action_starts parameter that allows you to specify a message the agent will speak before the action is triggered.

What is it? This optional string parameter lets you set a custom message that the agent will say before executing a custom action, providing better user experience and context during action execution.

EndpointTitle
POST /actionsCreate an action
PUT /actions/{action_id}Update an action
1"CUSTOM_ACTION": {
2   "http_mode": "GET",
3   "url": "https://example.com/api",
4   "message_before_action_starts": "Let me check that for you"
5 }