turn/start

Submits user input to a session; the optional disposition controls queue, steer, or replace when a turn is already running.

Parameters

Type: TurnStartParams

turn/start.providerRequestOptions is deliberately absent: RULED to stay off the published schema. The schema is the contract, and a free-form-object node kind is revisited only if the experimental field graduates. turn/start params.

Field	Type	Stability	Presence	Description
commandId	string		required	The idempotency handle (UUIDv7). The fresh turn’s turnId derives from it.
displayText	string		optional	Presentation form of the prompt for transcripts. Durable; carried on the resulting user-message view item. Never model-visible.
ifBusy	IfBusy		optional	Disposition when a turn is already running; default queue.
input	TurnInputPart[]		required	Ordered content parts; required and non-empty.
reasoningEffort	ReasoningEffort		optional	Reasoning tier sampled at submission for this turn.
sessionId	string		required	The target session.

Source

schema/msp/experimental/msp.schema.json#/methods/turn~2Fstart

{
  "description": "Submits user input to a session; the optional disposition controls queue, steer, or replace when a turn is already running.",
  "params": {
    "$ref": "#/$defs/TurnStartParams"
  },
  "result": {
    "$ref": "#/$defs/TurnStartResult"
  }
}