Rivumi normalizes each subagent dispatch into dependency waves of at most four nodes, runs read-only children concurrently in isolated workspaces, then makes the parent repeat hooks, approval, and transaction execution for any modification.
Rivumi parallelizes calls only when they are read-only, concurrency-safe, and classified as READ. Tool programs provide bounded read-only repeat and branching, while transactions snapshot and restore possible workspace-file changes; external side effects are not rolled back.
MongoDB fits aggregate-oriented data and evolving documents; the hard decisions are embedding, transaction boundaries, indexes, and shard keys.