useMessageMetadata

Read metadata recorded for a specific message id — today exposes parentCheckpointId, the checkpoint the message was first seen on. Designed for fork / edit flows:

<script lang="ts">
  const meta = useMessageMetadata(stream, () => selected?.id);
</script>
Parent: {meta.current?.parentCheckpointId ?? "root"}

messageId accepts a plain string or a getter — the binding re-evaluates whenever the id changes.