## Fork session

`live.sessions.fork(session_id, **kwargs) -> SessionForkResponse`

**post** `/live/sessions/{session_id}/fork`

Fork a stored Live session onto a new WebRTC connection.

### Parameters

- `session_id: String`

- `transport: Transport{ sdp, type}`

  WebRTC transport with an SDP offer for the new connection to the forked session.

  - `sdp: String`

    Session Description Protocol message for the WebRTC connection.

  - `type: :webrtc`

    The transport used for the Live session. Always `webrtc`.

    - `:webrtc`

- `session: MediaSessionForkConfig`

  Optional configuration overrides for the new Live session. Omit this object or send an empty object to inherit the stored session's settings.

  - `client: ClientConfig`

    Startup-only capabilities for an untrusted frontend attached to a unified WebRTC session. Trusted sideband connections are unaffected.

    - `data_channel: DataChannelConfig`

      Client and server event permissions for the WebRTC frontend data channel.

      - `allowed_client_events: :all | Array[String]`

        Client event types that the frontend data channel may send. Use 'all' to allow every client event; an empty array allows none. Omission preserves the existing allow-all behavior.

        - `AllowedClientEvents = :all`

          - `:all`

        - `UnionMember1 = Array[String]`

      - `allowed_server_events: :all | Array[ServerEventSelector]`

        Server events that may be sent to the frontend data channel. Use 'all' to allow every server event; an empty array allows none. Omission preserves the existing allow-all behavior. Responses events use an object with type 'response.event' and a response_event selector.

        - `AllowedServerEvents = :all`

          - `:all`

        - `EventSelectors = Array[ServerEventSelector]`

          - `type: String`

            The outer Live server event type. Use 'response.event' for Responses events.

          - `response_event: String`

            The nested Responses event type. Required when type is 'response.event'; forbidden for other event types.

  - `delegation: Delegation{ type, responses}`

    Update the Responses backend for an existing Live session without changing delegation ownership.

    - `type: :responses`

      The delegation owner. Always `responses` for tasks handled by the Responses API.

      - `:responses`

    - `responses: ResponsesDelegationUpdateConfig`

      Responses backend settings to update. Omitted settings keep their existing values.

      - `instructions: String`

        Instructions for the delegated Responses model, separate from Live instructions. See [backend prompting](/api/docs/guides/live-delegation#start-with-your-existing-backend-prompt).

      - `max_output_tokens: Integer`

        Maximum number of output tokens for each delegated response.

      - `model: String`

        The Responses backend model to use for subsequent delegated requests. Omit to keep the current backend model.

      - `parallel_tool_calls: bool`

        Whether the delegated Responses model may request multiple tool calls in a single response.

      - `reasoning: Reasoning{ effort, summary}`

        Reasoning settings passed to each delegated Responses request.

        - `effort: :none | :minimal | :low | 3 more`

          How much reasoning effort the delegated Responses model should use. Supported values depend on the backend model.

          - `:none`

          - `:minimal`

          - `:low`

          - `:medium`

          - `:high`

          - `:xhigh`

        - `summary: :concise | :detailed | :auto`

          The reasoning summary to request from the delegated Responses model, when supported.

          - `:concise`

          - `:detailed`

          - `:auto`

      - `service_tier: :auto | :default | :fast_tier_temp_pilot | 3 more`

        Service tier for delegated Responses requests.

        - `:auto`

        - `:default`

        - `:fast_tier_temp_pilot`

        - `:flex`

        - `:priority`

        - `:ultrafast`

      - `text: Text{ verbosity}`

        Text generation settings passed to each delegated Responses request.

        - `verbosity: :low | :medium | :high`

          The amount of detail in text generated by the Responses backend. This does not configure the Live model’s spoken delivery.

          - `:low`

          - `:medium`

          - `:high`

      - `tool_choice: :auto | :none | :required | LiveFunctionToolChoiceParam{ name, type} | LiveMCPToolChoiceParam{ name, server_label, type}`

        Controls which tool the Responses backend uses when handling a task delegated by the Live model.

        - `LiveToolChoiceEnum = :auto | :none | :required`

          - `:auto`

          - `:none`

          - `:required`

        - `class LiveFunctionToolChoiceParam`

          - `name: String`

          - `type: :function`

            - `:function`

        - `class LiveMCPToolChoiceParam`

          - `name: String`

          - `server_label: String`

          - `type: :mcp`

            - `:mcp`

      - `tools: Array[FunctionTool | WebSearch{ type}]`

        Tools available to the Responses backend while it handles tasks delegated by the Live model.

        - `class FunctionTool`

          A function tool available to the Responses backend when the Live model delegates a task.

          - `name: String`

            The name the delegated Responses model uses when calling this function.

          - `type: :function`

            The tool type. Always `function`.

            - `:function`

          - `description: String`

            What the function does and when the delegated Responses model should call it.

          - `parameters: Hash[Symbol, untyped]`

            A JSON Schema object describing the arguments accepted by the function.

          - `strict: bool`

            Whether the delegated Responses model must follow the function’s parameter schema exactly.

        - `class WebSearch`

          A web search tool available to the Live session’s Responses backend.

          - `type: :web_search`

            The tool type. Always `web_search`.

            - `:web_search`

  - `store: bool`

    Whether to store the forked session. Omission inherits the stored session's setting.

### Returns

- `class SessionForkResponse`

  The created Live session identifier and WebRTC answer. Apply transport.sdp as the peer's remote answer and wait for session.started on the data channel before sending commands.

  - `session: Session{ id}`

    The newly created Live session. Use its ID for session controls and sideband connections.

    - `id: String`

      Opaque session identifier. Preserve the returned value unchanged, including its prefix.

  - `transport: Transport{ sdp, type}`

    WebRTC transport with the SDP answer.

    - `sdp: String`

      Session Description Protocol message for the WebRTC connection.

    - `type: :webrtc`

      The transport used for the Live session. Always `webrtc`.

      - `:webrtc`

### Example

```ruby
require "openai"

openai = OpenAI::Client.new(api_key: "My API Key")

response = openai.live.sessions.fork("session_id", transport: {sdp: "x", type: :webrtc})

puts(response)
```

#### Response

```json
{
  "session": {
    "id": "id"
  },
  "transport": {
    "sdp": "x",
    "type": "webrtc"
  }
}
```