diff --git a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
index bfaa22c..31c7870 100644
--- a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
+++ b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
@@ -527,32 +527,66 @@ final class RemoteStore: ObservableObject {
         return cb
     }
 
-    /// Mirror the active connection's projection onto the flat @Published state the UI binds to.
-    private func mirrorActive() {
-        guard let c = activeConnection else { return }
-        connectivity = c.connectivity
-        hostName = c.hostName
-        sessions = c.sessions
-        capabilities = c.capabilities
-        grantedScope = c.grantedScope
-        modelCatalog = c.modelCatalog
-        dashboard = c.dashboard
-        meshPeers = c.meshPeers
+    /// Re-merge every connected Mac's projection into the flat @Published state the UI binds to
+    /// (mesh P3): all hosts' sessions and dashboards shown together, with the host-specific values
+    /// (host name, capabilities, catalog, connectivity, scope) following the open session's Mac —
+    /// or a representative one. No-op in demo, which seeds the aggregate directly.
+    private func rebuildAggregate() {
+        guard !demoMode else { return }
+        sessions = aggregatedSessions()
+        dashboard = DashboardSnapshot.merged(connections.values.map(\.dashboard))
+        meshPeers = connections.values.flatMap(\.meshPeers)
+
+        let ctx = contextConnection
+        hostName = ctx?.hostName ?? ""
+        capabilities = ctx?.capabilities
+            ?? WireCapabilities(canModifyToolInput: false, allowAlwaysScopes: [])
+        modelCatalog = ctx?.modelCatalog ?? .empty
+
+        if let id = openSessionHostID, let conn = connections[id] {
+            // While a transcript is open, the composer/controls act on *that* Mac — its connectivity
+            // gates send and its scope drives the control affordances.
+            connectivity = conn.connectivity
+            grantedScope = conn.grantedScope
+        } else {
+            connectivity = aggregateConnectivity()
+            // Optimistic new-chat gating: enabled if *any* Mac grants control (the owning Mac still
+            // enforces scope when the intent lands there).
+            grantedScope = connections.values
+                .filter { $0.connectivity.isLive }.map(\.grantedScope).max() ?? .approve
+        }
     }
 
-    /// Every connected Mac's live (non-archived) sessions — the aggregate the app-icon badge and
-    /// Live Activity summarize across hosts.
-    private var allLiveSessions: [WireSessionSummary] {
-        if demoMode { return demoHosts.flatMap(\.sessions).filter { !$0.archived } }
-        return connections.values.flatMap(\.sessions).filter { !$0.archived }
+    /// The flat sessions list: every connected Mac's sessions, deduped by id (ids are globally
+    /// unique). Views handle sorting/grouping.
+    private func aggregatedSessions() -> [WireSessionSummary] {
+        var seen = Set<SessionID>()
+        var result: [WireSessionSummary] = []
+        for conn in connections.values {
+            for summary in conn.sessions where seen.insert(summary.sessionID).inserted {
+                result.append(summary)
+            }
+        }
+        return result
+    }
+
+    /// One connectivity value for the whole app when no transcript is open (the chip + global
+    /// gating): connected if any Mac is live, else the most-informative in-progress/offline state.
+    private func aggregateConnectivity() -> Connectivity {
+        let all = connections.values.map(\.connectivity)
+        guard !all.isEmpty else { return .unpaired }
+        if let live = all.first(where: { $0.isLive }) { return live }
+        if all.contains(where: { if case .connecting = $0 { return true } else { return false } }) { return .connecting }
+        if all.contains(where: { if case .reconnecting = $0 { return true } else { return false } }) { return .reconnecting }
+        if all.contains(.hostOffline) { return .hostOffline }
+        return all.first ?? .unpaired
     }
 
     /// Refresh cross-host aggregates: the app-icon badge (needs-you across *all* Macs) + the Live
-    /// Activity summary.
+    /// Activity summary. `sessions`/`liveSessions` are already the merged aggregate.
     private func refreshAggregate() {
-        let needs = allLiveSessions.filter { $0.status.needsYou($0.disposition) }.count
-        NotificationRouter.shared.updateBadge(needs)
-        LiveActivityManager.shared.sync(hostName: hostName, sessions: allLiveSessions)
+        NotificationRouter.shared.updateBadge(needsYouCount)
+        LiveActivityManager.shared.sync(hostName: hostName, sessions: liveSessions)
     }
 
     /// Tear down every live connection (leaving the paired registry intact) — for entering demo.