diff --git a/extensions/signal/src/setup-managed-validation.test.ts b/extensions/signal/src/setup-managed-validation.test.ts
index 35d3e7a9a403..233e94b4304d 100644
--- a/extensions/signal/src/setup-managed-validation.test.ts
+++ b/extensions/signal/src/setup-managed-validation.test.ts
@@ -315,26 +315,58 @@ describe("probeManagedSignalSetup", () => {
     expect(mocks.spawnDaemon).not.toHaveBeenCalled();
   });
 
-  it("probes a separate connection URL with selected-account verification", async () => {
+  it("requires a separate connection URL to become healthy with the managed daemon", async () => {
     const candidate = { ...transport, url: "https://signal.example:9443" };
-    await probeManagedSignalSetup(
-      createParams(
-        {
-          channels: {
-            signal: {
-              accounts: {
-                work: { account, transport: candidate },
-              },
-            },
+    const cfg = {
+      channels: {
+        signal: {
+          accounts: {
+            work: { account, transport: candidate },
           },
         },
-        candidate,
-      ),
-    );
+      },
+    } as OpenClawConfig;
+    mocks.probeTransport
+      .mockResolvedValueOnce({ ok: false, error: "connection refused" })
+      .mockResolvedValueOnce({ ok: true, status: 200 })
+      .mockResolvedValueOnce({ ok: true, status: 200 });
+
+    await expect(probeManagedSignalSetup(createParams(cfg, candidate))).resolves.toMatchObject({
+      ok: true,
+    });
 
+    expect(mocks.probeTransport).toHaveBeenNthCalledWith(
+      1,
+      expect.not.objectContaining({ nativeAccountBinding: "owner-known-bound-account" }),
+    );
     expect(mocks.probeTransport).toHaveBeenNthCalledWith(
       2,
+      expect.objectContaining({ nativeAccountBinding: "owner-known-bound-account" }),
+    );
+    expect(mocks.probeTransport).toHaveBeenNthCalledWith(
+      3,
       expect.not.objectContaining({ nativeAccountBinding: "owner-known-bound-account" }),
     );
   });
+
+  it("rejects a separate connection URL already served by an independent daemon", async () => {
+    const candidate = { ...transport, url: "https://signal.example:9443" };
+    const cfg = {
+      channels: {
+        signal: {
+          accounts: {
+            work: { account, transport: candidate },
+          },
+        },
+      },
+    } as OpenClawConfig;
+
+    await expect(probeManagedSignalSetup(createParams(cfg, candidate))).resolves.toMatchObject({
+      ok: false,
+      error: expect.stringContaining("external-native"),
+    });
+
+    expect(mocks.probeTransport).toHaveBeenCalledOnce();
+    expect(mocks.spawnDaemon).not.toHaveBeenCalled();
+  });
 });
diff --git a/extensions/signal/src/setup-managed-validation.ts b/extensions/signal/src/setup-managed-validation.ts
index 38ff5b30b517..d3624fb6b710 100644
--- a/extensions/signal/src/setup-managed-validation.ts
+++ b/extensions/signal/src/setup-managed-validation.ts
@@ -79,6 +79,18 @@ async function probeManagedBind(params: {
   return result;
 }
 
+function hasSeparateConnectionUrl(params: {
+  transport: SignalManagedNativeTransport;
+  resolved: ResolvedManagedSignalTransport;
+}): boolean {
+  return !isSignalManagedNativeConnectionUrlForBind({
+    ...params.transport,
+    url: params.resolved.baseUrl,
+    httpHost: params.resolved.httpHost,
+    httpPort: params.resolved.httpPort,
+  });
+}
+
 async function probeSeparateConnectionUrl(params: {
   cfg: OpenClawConfig;
   accountId: string;
@@ -88,14 +100,7 @@ async function probeSeparateConnectionUrl(params: {
   abortSignal?: AbortSignal;
 }): Promise<SignalTransportProbeResult> {
   params.abortSignal?.throwIfAborted();
-  if (
-    isSignalManagedNativeConnectionUrlForBind({
-      ...params.transport,
-      url: params.resolved.baseUrl,
-      httpHost: params.resolved.httpHost,
-      httpPort: params.resolved.httpPort,
-    })
-  ) {
+  if (!hasSeparateConnectionUrl(params)) {
     return { ok: true, status: 200, error: null };
   }
   const result = await probeSignalTransport({
@@ -169,6 +174,16 @@ export async function probeManagedSignalSetup(params: {
       httpHost: resolved.httpHost,
       httpPort: resolved.httpPort,
     });
+    if (hasSeparateConnectionUrl({ ...params, resolved })) {
+      const preexistingConnection = await probeSeparateConnectionUrl({ ...params, resolved });
+      if (preexistingConnection.ok) {
+        return {
+          ok: false,
+          error:
+            "Signal managed connection URL was already serving the selected account before OpenClaw started its daemon. Use external-native for an independently operated Signal server.",
+        };
+      }
+    }
     params.abortSignal?.throwIfAborted();
     const spawnedDaemon = spawnSignalDaemon({
       cliPath: resolved.cliPath,