Events

Event	Detail
mlf-submit-request	User requested submit. Cancelable by the primitive layer.
mlf-submit-start	{ form, state } after submission starts.
mlf-submit-success	{ form, state, result, pipelineResult? } after success.
mlf-submit-abort	Abort notification for a canceled submit.
mlf-submit-error	{ form, state, error, status } after a failed submit.

mounted.host.addEventListener("mlf-submit-success", (event) => {
  const detail = (event as CustomEvent).detail;
  console.log(detail.pipelineResult?.reportFetchResults ?? detail.result.meta);
});

Prefer engine hooks for business logic. Use primitive events when integrating with host DOM systems. The primitive form controller also exposes subscribeTransitions() for the complete validation, submission, reset, restoration, and disposal sequence without converting those records into DOM events.