Limits

• A mirror is last-write-wins. Two tabs writing one KV document do not converge; use foldkit-sync when ordering and convergence matter.
• Arrays and objects use JSON in the URL by default; provide a codec for a more readable representation.
• Two different mirror kinds may observe the same Model field. That is not two owners; cold-load precedence follows the URL -> KV -> initial rule above.
• A URL mirror only touches the keys it owns. It composes with a Foldkit router's route.query(schema) when they use different keys.
• A cookie is sent with every request to its path, and browsers keep about 4 KB of one: mirror a few small fields there, not a document.
• Mirror stores have no durable operation log, conflict resolution, or multi-device synchronization.

See also#

• Mirrored state — the conceptual guide and package choice rules.
• foldkit-sync — state that must survive offline and converge.
• foldkit-remote — a cache of facts owned by the server.
• examples/todo-app — a linkable filter and a remembered draft in a real application.