RCA REFINEMENT (twohost red), replaces the "in-process bound port" fix shape I sent earlier: serve_for runs in the BRAIN child (brainproc.rs:422-440); the docs listener + bound port live in the BROKER (daemon.rs:310-316). The brain's IPC ask is by design; the defect is that webproxy.rs:522 asks the CANONICAL seed name instead of the broker the brain is connected to, and the twohost rig's role B hosts its brain under an invented broker name with no docs listener (A binds both). On Linux abstract-namespace UDS an unbound name = ECONNREFUSED. Still a candidate-introduced red under REQ-WEB-URL-BOUND-PORT (never publish a URL for an unbound listener), still deterministic, still no rerun. S5 shape = product half (todlando: ask the owning broker + single-host regression cell red-on-S4/green-on-fix) + rig half (hertz: role B answers DocsStatus and binds a broker-backed docs listener). Both GO'd for build+measure on isolated targets now; S5 assembly/push waits for Reavo's proceed/hold. Note updated: golden-34946493637/twohost-red-rca.md.