diff --git a/src/backend/hosts/metrics/index.ts b/src/backend/hosts/metrics/index.ts
index 8f71f1d9..b4baddd3 100644
--- a/src/backend/hosts/metrics/index.ts
+++ b/src/backend/hosts/metrics/index.ts
@@ -857,6 +857,36 @@ app.use((_req, res, next) => {
   next();
 });
 
+// Internal endpoint — only accepts calls from localhost.
+// Used by the main backend to notify the metrics service of SSH login events.
+app.post("/internal/login-alert", async (req, res) => {
+  const remoteIp = req.socket.remoteAddress;
+  if (
+    remoteIp !== "127.0.0.1" &&
+    remoteIp !== "::1" &&
+    remoteIp !== "::ffff:127.0.0.1"
+  ) {
+    return res.status(403).json({ error: "Forbidden" });
+  }
+  const systemCrypto = (await import("../../utils/system-crypto.js"))
+    .SystemCrypto;
+  const expectedToken = await systemCrypto.getInstance().getInternalAuthToken();
+  const token = req.headers["x-internal-auth"];
+  if (!token || token !== expectedToken) {
+    return res.status(403).json({ error: "Forbidden" });
+  }
+  const { hostId, userId, sshUser, fromIp } = req.body as {
+    hostId: number;
+    userId: string;
+    sshUser: string;
+    fromIp: string;
+  };
+  AlertEngine.getInstance()
+    .evaluateUserLogin(hostId, userId, sshUser, fromIp)
+    .catch(() => {});
+  res.json({ ok: true });
+});
+
 app.use(authManager.createAuthMiddleware());
 const requireAdmin = authManager.createAdminMiddleware();
 
@@ -2803,36 +2833,6 @@ registerManagerRoutes(app, {
   },
 });
 
-// Internal endpoint — only accepts calls from localhost.
-// Used by the main backend to notify the metrics service of SSH login events.
-app.post("/internal/login-alert", async (req, res) => {
-  const remoteIp = req.socket.remoteAddress;
-  if (
-    remoteIp !== "127.0.0.1" &&
-    remoteIp !== "::1" &&
-    remoteIp !== "::ffff:127.0.0.1"
-  ) {
-    return res.status(403).json({ error: "Forbidden" });
-  }
-  const systemCrypto = (await import("../../utils/system-crypto.js"))
-    .SystemCrypto;
-  const expectedToken = await systemCrypto.getInstance().getInternalAuthToken();
-  const token = req.headers["x-internal-auth"];
-  if (!token || token !== expectedToken) {
-    return res.status(403).json({ error: "Forbidden" });
-  }
-  const { hostId, userId, sshUser, fromIp } = req.body as {
-    hostId: number;
-    userId: string;
-    sshUser: string;
-    fromIp: string;
-  };
-  AlertEngine.getInstance()
-    .evaluateUserLogin(hostId, userId, sshUser, fromIp)
-    .catch(() => {});
-  res.json({ ok: true });
-});
-
 process.on("SIGINT", () => {
   pollingManager.destroy();
   connectionPool.destroy();
diff --git a/src/backend/tests/utils/alert-trigger.test.ts b/src/backend/tests/utils/alert-trigger.test.ts
new file mode 100644
index 00000000..d4ed63c1
--- /dev/null
+++ b/src/backend/tests/utils/alert-trigger.test.ts
@@ -0,0 +1,48 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { triggerLoginAlert } from "../../utils/alert-trigger.js";
+import { SystemCrypto } from "../../utils/system-crypto.js";
+import { sshLogger } from "../../utils/logger.js";
+
+describe("triggerLoginAlert", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("reports a rejected metrics-service request", async () => {
+    vi.spyOn(SystemCrypto, "getInstance").mockReturnValue({
+      getInternalAuthToken: vi.fn().mockResolvedValue("internal-token"),
+    } as never);
+    vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response('{"error":"Missing authentication token"}', {
+        status: 401,
+      }),
+    );
+    const warn = vi.spyOn(sshLogger, "warn").mockImplementation(() => {});
+
+    await triggerLoginAlert(7, "user-1", "root", "192.0.2.1");
+
+    expect(warn).toHaveBeenCalledWith(
+      "Failed to trigger login alert",
+      expect.objectContaining({
+        operation: "login_alert_trigger_error",
+        hostId: 7,
+        error:
+          'Metrics service returned 401: {"error":"Missing authentication token"}',
+      }),
+    );
+  });
+
+  it("does not log a warning when the metrics service accepts the event", async () => {
+    vi.spyOn(SystemCrypto, "getInstance").mockReturnValue({
+      getInternalAuthToken: vi.fn().mockResolvedValue("internal-token"),
+    } as never);
+    vi.spyOn(globalThis, "fetch").mockResolvedValue(
+      new Response('{"ok":true}', { status: 200 }),
+    );
+    const warn = vi.spyOn(sshLogger, "warn").mockImplementation(() => {});
+
+    await triggerLoginAlert(7, "user-1", "root", "192.0.2.1");
+
+    expect(warn).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/backend/utils/alert-trigger.ts b/src/backend/utils/alert-trigger.ts
index c716465b..2098bec0 100644
--- a/src/backend/utils/alert-trigger.ts
+++ b/src/backend/utils/alert-trigger.ts
@@ -11,14 +11,23 @@ export async function triggerLoginAlert(
 ): Promise<void> {
   try {
     const token = await SystemCrypto.getInstance().getInternalAuthToken();
-    await fetch(`${METRICS_SERVICE_URL}/internal/login-alert`, {
-      method: "POST",
-      headers: {
-        "Content-Type": "application/json",
-        "x-internal-auth": token,
+    const response = await fetch(
+      `${METRICS_SERVICE_URL}/internal/login-alert`,
+      {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+          "x-internal-auth": token,
+        },
+        body: JSON.stringify({ hostId, userId, sshUser, fromIp }),
       },
-      body: JSON.stringify({ hostId, userId, sshUser, fromIp }),
-    });
+    );
+    if (!response.ok) {
+      const details = await response.text();
+      throw new Error(
+        `Metrics service returned ${response.status}${details ? `: ${details}` : ""}`,
+      );
+    }
   } catch (err) {
     sshLogger.warn("Failed to trigger login alert", {
       operation: "login_alert_trigger_error",