@type t() :: %OpenCode.Generated.SessionNextStepEndedData{
  assistant_message_id: String.t(),
  cost: number(),
  files: [String.t()] | nil,
  finish: String.t(),
  session_id: String.t(),
  snapshot: String.t() | nil,
  timestamp: number(),
  tokens: OpenCode.Generated.SessionNextStepEndedDataTokens.t()
}