Upsert the open draft on this branch. If no draft is open, one is created automatically. The request body is an agent config partial in the same camelCase shape as GET /agent/{id} (globalPrompt, firstMessage, synthesizer, language, voiceDetectionConfig, smartTurnConfig, ...) and must contain at least one recognized field; the server merges it into the existing draft and returns the resulting draft as a revision-shaped snapshot.

Send native JSON types, not stringified values. Arrays (language.supported: ["en"]), booleans (language.switching.isEnabled: false), and objects (timezone: {"label": "(GMT+5:30) Asia/Kolkata", "offset": 330}) must be sent as real JSON. Passing "[\"en\"]", "false", or "Asia/Kolkata" instead is refused with a Zod-style error naming the offending path and the received type (e.g. Invalid config: language.supported: Expected array, received string). This is the single most common integration bug on this endpoint.

Publish the draft with POST /agent/{id}/branches/{branchId}/draft/publish to make the changes live. The draft PUT alone does not affect running calls.

{
  "timezone": {
    "label": "(GMT+5:30) Asia/Kolkata",
    "offset": 330
  }
}

{
  "status": true
}