# Artifacts Clusterflux separates artifact metadata from artifact bytes. ## Publish metadata `flush()` makes a VFS artifact visible to downstream tasks and records its digest, size, producer task and attempt, and retaining locations. It does not upload bytes to the coordinator by default. Your node retains artifact bytes on a best-effort basis. If every retaining node is lost, stale, revoked, or garbage-collects the bytes, the artifact is unavailable. Clusterflux reports that state instead of inventing durable storage. ## Move bytes explicitly Use `sync()` or an explicit export when you need another node or your own storage system to hold the bytes. Same-node reuse avoids a coordinator transfer. ## Download ~~~bash clusterflux artifact list --process clusterflux artifact download --to ./output.bin --max-bytes 67108864 ~~~ Before returning a link, the service checks authorization, current retention, source-node liveness, live size, per-project and per-account policy, and relay capacity. It reserves the affordable ingress and egress budget atomically. The scoped link is unguessable, expires, can be revoked, and is bound to the actor, tenant, project, process, artifact, and policy context. The reverse stream counts framing, base64 expansion, failed bytes, and abandoned transfers. The CLI verifies the final digest. Hosted policy may impose per-project, per-tenant, and per-account size, concurrency, and period limits. Operators may disable relay traffic as an emergency safety control; one tenant's period usage does not consume a shared customer byte quota.