diff --git a/apps/ios/Sources/Model/NodeAppModel.swift b/apps/ios/Sources/Model/NodeAppModel.swift
index 1d09251dd76..ef2f375296b 100644
--- a/apps/ios/Sources/Model/NodeAppModel.swift
+++ b/apps/ios/Sources/Model/NodeAppModel.swift
@@ -1603,6 +1603,14 @@ extension NodeAppModel {
         return SessionKey.makeAgentSessionKey(agentId: agentId, baseKey: base)
     }
 
+    var chatSessionKey: String {
+        let base = "ios"
+        let agentId = (self.selectedAgentId ?? "").trimmingCharacters(in: .whitespacesAndNewlines)
+        let defaultId = (self.gatewayDefaultAgentId ?? "").trimmingCharacters(in: .whitespacesAndNewlines)
+        if agentId.isEmpty || (!defaultId.isEmpty && agentId == defaultId) { return base }
+        return SessionKey.makeAgentSessionKey(agentId: agentId, baseKey: base)
+    }
+
     var activeAgentName: String {
         let agentId = (self.selectedAgentId ?? "").trimmingCharacters(in: .whitespacesAndNewlines)
         let defaultId = (self.gatewayDefaultAgentId ?? "").trimmingCharacters(in: .whitespacesAndNewlines)
diff --git a/apps/ios/Sources/RootCanvas.swift b/apps/ios/Sources/RootCanvas.swift
index 70ba9cdb96f..da893d3c943 100644
--- a/apps/ios/Sources/RootCanvas.swift
+++ b/apps/ios/Sources/RootCanvas.swift
@@ -99,7 +99,7 @@ struct RootCanvas: View {
                 ChatSheet(
                     // Chat RPCs run on the operator session (read/write scopes).
                     gateway: self.appModel.operatorSession,
-                    sessionKey: self.appModel.mainSessionKey,
+                    sessionKey: self.appModel.chatSessionKey,
                     agentName: self.appModel.activeAgentName,
                     userAccent: self.appModel.seamColor)
             case .quickSetup:
diff --git a/apps/ios/Tests/NodeAppModelInvokeTests.swift b/apps/ios/Tests/NodeAppModelInvokeTests.swift
index f5f40fc8b7c..403c08f5c73 100644
--- a/apps/ios/Tests/NodeAppModelInvokeTests.swift
+++ b/apps/ios/Tests/NodeAppModelInvokeTests.swift
@@ -77,6 +77,19 @@ private final class MockWatchMessagingService: WatchMessagingServicing, @uncheck
         #expect(json.contains("\"value\""))
     }
 
+    @Test @MainActor func chatSessionKeyDefaultsToIOSBase() {
+        let appModel = NodeAppModel()
+        #expect(appModel.chatSessionKey == "ios")
+    }
+
+    @Test @MainActor func chatSessionKeyUsesAgentScopedKeyForNonDefaultAgent() {
+        let appModel = NodeAppModel()
+        appModel.gatewayDefaultAgentId = "main"
+        appModel.setSelectedAgentId("agent-123")
+        #expect(appModel.chatSessionKey == SessionKey.makeAgentSessionKey(agentId: "agent-123", baseKey: "ios"))
+        #expect(appModel.mainSessionKey == "agent:agent-123:main")
+    }
+
     @Test @MainActor func handleInvokeRejectsBackgroundCommands() async {
         let appModel = NodeAppModel()
         appModel.setScenePhase(.background)