diff --git a/extensions/signal/src/client-adapter.test.ts b/extensions/signal/src/client-adapter.test.ts
index 30e7bad65b4..5028b89a952 100644
--- a/extensions/signal/src/client-adapter.test.ts
+++ b/extensions/signal/src/client-adapter.test.ts
@@ -159,6 +159,16 @@ describe("detectSignalApiMode", () => {
     expect(result).toBe("native");
   });
 
+  it("prefers native even when the container probe resolves first", async () => {
+    mockNativeCheck.mockImplementation(
+      () => new Promise((resolve) => setTimeout(() => resolve({ ok: true, status: 200 }), 1)),
+    );
+    mockContainerCheck.mockResolvedValue({ ok: true, status: 200 });
+
+    const result = await detectSignalApiMode("http://localhost:8080");
+    expect(result).toBe("native");
+  });
+
   it("throws error when neither endpoint responds", async () => {
     mockNativeCheck.mockResolvedValue({ ok: false, status: null, error: "Connection refused" });
     mockContainerCheck.mockResolvedValue({ ok: false, status: null, error: "Connection refused" });
@@ -530,6 +540,26 @@ describe("streamSignalEvents", () => {
       "+14259798283",
     );
   });
+
+  it("does not reuse a cached container mode for no-account receive streams", async () => {
+    setApiMode("auto");
+    mockNativeCheck.mockResolvedValue({ ok: false, status: 404 });
+    mockContainerCheck.mockResolvedValue({ ok: true, status: 200 });
+
+    await expect(signalCheck("http://auto-cache-no-account.local:8080")).resolves.toEqual({
+      ok: true,
+      status: 200,
+    });
+
+    await expect(
+      streamSignalEvents({
+        baseUrl: "http://auto-cache-no-account.local:8080",
+        onEvent: vi.fn(),
+      }),
+    ).rejects.toThrow("Signal API not reachable at http://auto-cache-no-account.local:8080");
+    expect(mockStreamContainerEvents).not.toHaveBeenCalled();
+    expect(mockContainerCheck).toHaveBeenCalledTimes(2);
+  });
 });
 
 describe("fetchAttachment", () => {
diff --git a/extensions/signal/src/client-adapter.ts b/extensions/signal/src/client-adapter.ts
index 56721c163de..c0410036a11 100644
--- a/extensions/signal/src/client-adapter.ts
+++ b/extensions/signal/src/client-adapter.ts
@@ -65,7 +65,7 @@ async function resolveAutoApiMode(
     if (
       cached.mode !== "container" ||
       !options.requireContainerReceive ||
-      cached.receiveAccount === options.account
+      (Boolean(options.account?.trim()) && cached.receiveAccount === options.account?.trim())
     ) {
       return cached.mode;
     }
@@ -103,32 +103,29 @@ async function resolveApiModeForOperation(params: {
 
 /**
  * Detect which Signal API mode is available by probing endpoints.
- * First endpoint to respond OK wins.
+ * Native wins when both APIs are healthy because it preserves the richer JSON-RPC contract.
  */
 export async function detectSignalApiMode(
   baseUrl: string,
   timeoutMs = DEFAULT_TIMEOUT_MS,
   options: { account?: string; requireContainerReceive?: boolean } = {},
 ): Promise<"native" | "container"> {
-  const nativePromise = nativeCheck(baseUrl, timeoutMs).then((r) =>
-    r.ok ? ("native" as const) : Promise.reject(new Error("native not ok")),
-  );
   const containerAccount = options.requireContainerReceive ? options.account?.trim() : undefined;
+  const nativePromise = nativeCheck(baseUrl, timeoutMs).catch(() => ({ ok: false }));
   const containerPromise = containerAccount
-    ? containerCheck(baseUrl, timeoutMs, containerAccount).then((r) =>
-        r.ok ? ("container" as const) : Promise.reject(new Error("container not ok")),
-      )
+    ? containerCheck(baseUrl, timeoutMs, containerAccount).catch(() => ({ ok: false }))
     : options.requireContainerReceive
-      ? Promise.reject(new Error("container receive account required"))
-      : containerCheck(baseUrl, timeoutMs).then((r) =>
-          r.ok ? ("container" as const) : Promise.reject(new Error("container not ok")),
-        );
+      ? Promise.resolve({ ok: false })
+      : containerCheck(baseUrl, timeoutMs).catch(() => ({ ok: false }));
 
-  try {
-    return await Promise.any([nativePromise, containerPromise]);
-  } catch {
-    throw new Error(`Signal API not reachable at ${baseUrl}`);
+  const [nativeResult, containerResult] = await Promise.all([nativePromise, containerPromise]);
+  if (nativeResult.ok) {
+    return "native";
   }
+  if (containerResult.ok) {
+    return "container";
+  }
+  throw new Error(`Signal API not reachable at ${baseUrl}`);
 }
 
 /**
diff --git a/extensions/twitch/src/twitch-client.test.ts b/extensions/twitch/src/twitch-client.test.ts
index 9a9dbc04bbe..1d907234385 100644
--- a/extensions/twitch/src/twitch-client.test.ts
+++ b/extensions/twitch/src/twitch-client.test.ts
@@ -186,6 +186,21 @@ describe("TwitchClientManager", () => {
       expect(mockConnect).toHaveBeenCalledTimes(1);
     });
 
+    it("deduplicates concurrent client creation for the same account", async () => {
+      mockConnect.mockImplementationOnce(() => {});
+
+      const first = manager.getClient(testAccount);
+      const second = manager.getClient(testAccount);
+      await Promise.resolve();
+
+      expect(mockConnect).toHaveBeenCalledTimes(1);
+      expect(authSuccessHandlers).toHaveLength(1);
+      authSuccessHandlers[0]?.();
+
+      const [client1, client2] = await Promise.all([first, second]);
+      expect(client1).toBe(client2);
+    });
+
     it("should create separate clients for different accounts", async () => {
       await manager.getClient(testAccount);
       await manager.getClient(testAccount2);