The join command never emits --bridge-cidr or --host-network

open   by a73x

Labels: backlog

[claude 2026-08-18] Carried in notes as #35. The web join flow builds the agent
command line (web/src/lib joinCommands / JoinHost.svelte) and emits neither flag,
so a host that needs a non-default guest subnet, or that is meant to advertise a
named network, joins wrong and has to be hand-edited in its unit afterwards. The
agent side already supports both (internal/agent/netenv/uplink.go names
--bridge-cidr in its refusal; --host-network is the v0.0.7 feature). Decide which
belong in the generated command and which belong in a post-join edit.