@type t() :: %Synaptic.Step{
  input: map(),
  llm_branches: list(),
  max_retries: non_neg_integer(),
  name: atom(),
  output: map(),
  resume_schema: map(),
  scorers: list(),
  suspend?: boolean(),
  type: :sequential | :parallel | :async | :llm,
  validation: keyword(),
  validation_declared: keyword() | map() | nil
}