Agents read vpc-id from EC2 IMDS on auth; the server scopes subnet_primary_seeder to vpc-id with /24 fallback, exposes VPC seeder badges, and documents cross-VPC gossip via peering/TGW.
Server Reed-Solomon 4+2 shard encode on deploy plans when erasure_lanes_enabled; agents reassemble from parallel lane URLs as staging fallback with BGP/Path Tracer hints.