# K1 launch nodes
`LaunchNodes` reexports `Authority`, `GroupId`, `TxId`, `UserId`, `NodeId`, `TargetName`, and `TargetId` through the codec. `TargetName` therefore retains the codec's exact case-sensitive validation and text-preserving behavior.
`LaunchNodes::open(path, ordering, peering)` requires exclusive single-process ownership of `path`. The append-only v3 file is only a fast startup projection. KTO callbacks for subsystem `k1-launch-nodes` are the sole normal authority for appends and bindings. Startup validates a recovered checkpoint against canonical KTO state, registers after that checkpoint, and replays through the same callback used for live delivery.
A missing or empty projection is initialized and synchronized. An incomplete final record is truncated and synchronized. Complete malformed or checksum-invalid v3 content resets the disposable projection before canonical replay. A nonempty non-v3 file, including v2, is rejected with no migration or silent discard.
`get(&TargetId)` returns the current canonical binding. `set(TargetId, NodeId)` creates one strict version-1 Set action with a random operation ID and submits it through Peering exactly once. It does not append directly or retry. Successful matching callback evidence controls the result; callback evidence wins over a Peering error. A Peering error without evidence reports the submission error.
An append is published in memory only after `write_all` and `sync_data`. A process crash after KTO commit but before or during projection persistence is ambiguous to that caller; a fresh open validates or rebuilds the projection from canonical history. Complete records that survive an error are resolved only by fresh open.
Malformed callbacks, contradictory callback evidence, persistence failures, and reorganization permanently fault that facade instance and clear pending operations. Reads then fail. Fresh open is the only recovery path. There is no live repair, rollback, worker, polling, timeout, arbitrary cap, second authority, or multiprocess coordination.