diff --git a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
index 68ad3e3..7d3c90d 100644
--- a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
+++ b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
@@ -843,3 +843,41 @@ extension Data {
         DeviceIdentity.fingerprint(ofStaticKey: self)
     }
 }
+
+extension WireSessionSummary {
+    /// A copy with selected fields overridden — the demo simulator's only way to "mutate" a
+    /// summary, whose stored properties are all `let`. Nullable fields use a double optional so a
+    /// caller can distinguish "keep" (omit) from "set to nil" (`.some(nil)`). `updatedAt` bumps
+    /// to now unless given. Only the fields the simulator touches are exposed.
+    func demoCopy(
+        status: SessionStatus? = nil,
+        disposition: TurnDisposition?? = nil,
+        title: String? = nil,
+        favorite: Bool? = nil,
+        archived: Bool? = nil,
+        pendingApprovalCount: Int? = nil,
+        diffStat: DiffStat?? = nil,
+        model: String?? = nil,
+        effort: String?? = nil,
+        auto: Bool? = nil,
+        autoShip: Bool? = nil,
+        shipBranch: String?? = nil,
+        updatedAt: Date? = nil
+    ) -> WireSessionSummary {
+        WireSessionSummary(
+            sessionID: sessionID, projectID: projectID, projectName: projectName, backend: backend,
+            status: status ?? self.status,
+            disposition: disposition ?? self.disposition,
+            title: title ?? self.title, branch: branch, lastSeq: lastSeq,
+            diffStat: diffStat ?? self.diffStat,
+            pendingApprovalCount: pendingApprovalCount ?? self.pendingApprovalCount,
+            favorite: favorite ?? self.favorite,
+            archived: archived ?? self.archived,
+            queuedMessage: queuedMessage, queuedMessages: queuedMessages,
+            model: model ?? self.model, effort: effort ?? self.effort,
+            auto: auto ?? self.auto, autoShip: autoShip ?? self.autoShip,
+            shipBranch: shipBranch ?? self.shipBranch,
+            contextInputTokens: contextInputTokens,
+            updatedAt: updatedAt ?? Date())
+    }
+}