diff --git a/ui/src/ui/app-gateway.sessions.node.test.ts b/ui/src/ui/app-gateway.sessions.node.test.ts
index c4d2a45f1da..b9382a62bcc 100644
--- a/ui/src/ui/app-gateway.sessions.node.test.ts
+++ b/ui/src/ui/app-gateway.sessions.node.test.ts
@@ -150,7 +150,7 @@ describe("handleGatewayEvent sessions.changed", () => {
     expect(loadSessionsMock).not.toHaveBeenCalled();
   });
 
-  it("reloads sessions when an applied message-phase event inserts a session row", () => {
+  it("does not reload sessions when a message-phase event inserts a session row", () => {
     loadSessionsMock.mockReset();
     applySessionsChangedEventMock
       .mockReset()
@@ -170,11 +170,10 @@ describe("handleGatewayEvent sessions.changed", () => {
     });
 
     expect(applySessionsChangedEventMock).toHaveBeenCalledTimes(1);
-    expect(loadSessionsMock).toHaveBeenCalledTimes(1);
-    expect(loadSessionsMock).toHaveBeenCalledWith(host);
+    expect(loadSessionsMock).not.toHaveBeenCalled();
   });
 
-  it("reloads sessions when a message-phase event cannot patch local state", () => {
+  it("does not reload sessions when a message-phase event cannot patch local state", () => {
     loadSessionsMock.mockReset();
     applySessionsChangedEventMock.mockReset().mockReturnValue({ applied: false });
     const host = createHost();
@@ -186,8 +185,39 @@ describe("handleGatewayEvent sessions.changed", () => {
       seq: 1,
     });
 
-    expect(loadSessionsMock).toHaveBeenCalledTimes(1);
-    expect(loadSessionsMock).toHaveBeenCalledWith(host);
+    expect(loadSessionsMock).not.toHaveBeenCalled();
+  });
+
+  it("does not reload sessions for chat lifecycle events", () => {
+    loadSessionsMock.mockReset();
+    applySessionsChangedEventMock.mockReset().mockReturnValue({ applied: true, change: "updated" });
+    const host = createHost();
+
+    handleGatewayEvent(host, {
+      type: "event",
+      event: "sessions.changed",
+      payload: { sessionKey: "agent:main:main", phase: "start", runId: "run-1" },
+      seq: 1,
+    });
+
+    expect(applySessionsChangedEventMock).toHaveBeenCalledTimes(1);
+    expect(loadSessionsMock).not.toHaveBeenCalled();
+  });
+
+  it("does not reload sessions for chat send acknowledgement events", () => {
+    loadSessionsMock.mockReset();
+    applySessionsChangedEventMock.mockReset().mockReturnValue({ applied: true, change: "updated" });
+    const host = createHost();
+
+    handleGatewayEvent(host, {
+      type: "event",
+      event: "sessions.changed",
+      payload: { sessionKey: "agent:main:main", reason: "send" },
+      seq: 1,
+    });
+
+    expect(applySessionsChangedEventMock).toHaveBeenCalledTimes(1);
+    expect(loadSessionsMock).not.toHaveBeenCalled();
   });
 });
 
diff --git a/ui/src/ui/app-gateway.ts b/ui/src/ui/app-gateway.ts
index eafddc934c2..7257bc60cc5 100644
--- a/ui/src/ui/app-gateway.ts
+++ b/ui/src/ui/app-gateway.ts
@@ -156,12 +156,18 @@ function isTerminalChatState(
   return state === "final" || state === "aborted" || state === "error";
 }
 
-function isSessionMessagePhasePayload(payload: unknown): boolean {
+function isChatTurnSessionChangedPayload(payload: unknown): boolean {
+  if (!payload || typeof payload !== "object" || Array.isArray(payload)) {
+    return false;
+  }
+  const record = payload as { phase?: unknown; reason?: unknown };
   return (
-    Boolean(payload) &&
-    typeof payload === "object" &&
-    !Array.isArray(payload) &&
-    (payload as { phase?: unknown }).phase === "message"
+    record.phase === "start" ||
+    record.phase === "message" ||
+    record.phase === "end" ||
+    record.phase === "error" ||
+    record.reason === "send" ||
+    record.reason === "steer"
   );
 }
 
@@ -749,12 +755,8 @@ function handleGatewayEventUnsafe(host: GatewayHost, evt: GatewayEventFrame) {
   }
 
   if (evt.event === "sessions.changed") {
-    const applyResult = applySessionsChangedEvent(host as unknown as SessionsState, evt.payload);
-    if (
-      applyResult.applied &&
-      applyResult.change === "updated" &&
-      isSessionMessagePhasePayload(evt.payload)
-    ) {
+    applySessionsChangedEvent(host as unknown as SessionsState, evt.payload);
+    if (isChatTurnSessionChangedPayload(evt.payload)) {
       return;
     }
     void loadSessions(host as unknown as SessionsState);