diff --git a/packages/server/src/server/hub/relationship-liveness.test.ts b/packages/server/src/server/hub/relationship-liveness.test.ts
new file mode 100644
index 0000000000..048ee8ff80
--- /dev/null
+++ b/packages/server/src/server/hub/relationship-liveness.test.ts
@@ -0,0 +1,161 @@
+import { createServer as createHttpServer } from "node:http";
+import { connect, createServer as createTcpServer, type AddressInfo, type Socket } from "node:net";
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import pino from "pino";
+import { expect, test, vi } from "vitest";
+import { WebSocket, WebSocketServer } from "ws";
+import { HubRelationshipController } from "./relationship-controller.js";
+import { DirectHubRelationshipRemote } from "./relationship-remote.js";
+
+test("a silently lost Hub connection leaves connected state and reconnects when the path recovers", async () => {
+  const home = await mkdtemp(path.join(tmpdir(), "paseo-hub-liveness-"));
+  const hub = createHttpServer(async (request, response) => {
+    let body = "";
+    for await (const chunk of request) body += chunk;
+    const enrollment = JSON.parse(body) as { daemonId: string };
+    response.writeHead(200, { "content-type": "application/json" }).end(
+      JSON.stringify({
+        daemonId: enrollment.daemonId,
+        permissions: ["hub.execute"],
+        webSocketUrl: `ws://127.0.0.1:${proxyPort}/api/daemons/socket`,
+      }),
+    );
+  });
+  const webSockets = new WebSocketServer({ server: hub });
+  const peers = new Set<WebSocket>();
+  let connections = 0;
+  let pongs = 0;
+  webSockets.on("connection", (peer) => {
+    connections += 1;
+    peers.add(peer);
+    peer.on("close", () => peers.delete(peer));
+  });
+  await listen(hub);
+  const hubPort = (hub.address() as AddressInfo).port;
+  const streams = new Set<Socket>();
+  let dropped = false;
+  const proxy = createTcpServer((client) => {
+    const upstream = connect(hubPort, "127.0.0.1");
+    streams.add(client);
+    streams.add(upstream);
+    client.on("data", (data) => {
+      if (!dropped) upstream.write(data);
+    });
+    upstream.on("data", (data) => {
+      if (!dropped) client.write(data);
+    });
+    client.on("end", () => {
+      if (!dropped) upstream.end();
+    });
+    upstream.on("end", () => {
+      if (!dropped) client.end();
+    });
+    for (const socket of [client, upstream]) {
+      socket.on("error", () => socket.destroy());
+      socket.on("close", () => streams.delete(socket));
+    }
+  });
+  await listen(proxy);
+  const proxyPort = (proxy.address() as AddressInfo).port;
+  let retry: (() => void) | undefined;
+  const controller = new HubRelationshipController({
+    paseoHome: home,
+    hostname: "test-daemon",
+    serverId: "server-1",
+    daemonPublicKey: "public-key",
+    logger: pino({ level: "silent" }),
+    remote: new DirectHubRelationshipRemote(),
+    clock: {
+      now: () => new Date(),
+      schedule: (_delay, task) => {
+        retry = task;
+        return { cancel: () => (retry = undefined) };
+      },
+    },
+    attachSocket: async (socket) => {
+      if (!(socket instanceof WebSocket)) throw new Error("Expected a real WebSocket");
+      socket.on("pong", () => (pongs += 1));
+    },
+    updateAttachedPermissions: () => undefined,
+    createExecutionAgents: () => ({
+      create: async () => {
+        throw new Error("Unexpected agent creation");
+      },
+      subscribe: () => () => undefined,
+      invalidateAuthority: async () => undefined,
+    }),
+  });
+
+  try {
+    // Keep TCP and WebSocket I/O real; accelerate only the keepalive interval and its clock.
+    vi.useFakeTimers({ toFake: ["setInterval", "clearInterval", "Date"] });
+    await controller.connect({
+      hubUrl: `http://127.0.0.1:${proxyPort}`,
+      token: "test-token",
+      permissions: ["hub.execute"],
+    });
+    await expect.poll(() => controller.status().state).toBe("connected");
+    const connectedAt = controller.status().connectedAt;
+
+    expect(connections).toBe(1);
+
+    // Model the reported proxy request ending without a close reaching the daemon.
+    dropped = true;
+    for (const peer of peers) peer.terminate();
+    await expect.poll(() => peers.size).toBe(0);
+    await vi.advanceTimersByTimeAsync(60_000);
+    await expect.poll(() => controller.status().state).toBe("reconnecting");
+    expect(controller.status().lastError).toBe("Hub WebSocket heartbeat timed out");
+    expect(retry).toBeTypeOf("function");
+
+    dropped = false;
+    retry?.();
+    await expect.poll(() => controller.status().state).toBe("connected");
+    expect(connections).toBe(2);
+    expect(controller.status().connectedAt).not.toBe(connectedAt);
+    expect(controller.status().lastError).toBeNull();
+
+    // A healthy idle connection survives multiple liveness windows.
+    for (let tick = 0; tick < 12; tick += 1) {
+      const before = pongs;
+      await vi.advanceTimersByTimeAsync(10_000);
+      await expect.poll(() => pongs).toBeGreaterThan(before);
+    }
+    expect(controller.status().state).toBe("connected");
+    expect(connections).toBe(2);
+
+    await controller.stop();
+    await expect.poll(() => peers.size).toBe(0);
+    await expect.poll(() => vi.getTimerCount()).toBe(0);
+  } finally {
+    await controller.stop();
+    vi.useRealTimers();
+    for (const socket of streams) socket.destroy();
+    for (const peer of peers) peer.terminate();
+    webSockets.close();
+    await Promise.all([close(proxy), close(hub)]);
+    await rm(home, { recursive: true, force: true });
+  }
+});
+
+async function listen(
+  server: ReturnType<typeof createTcpServer> | ReturnType<typeof createHttpServer>,
+) {
+  await new Promise<void>((resolve) => server.listen(0, "127.0.0.1", resolve));
+}
+
+async function close(
+  server: ReturnType<typeof createTcpServer> | ReturnType<typeof createHttpServer>,
+) {
+  await new Promise<void>((resolve, reject) => {
+    server.close((error) => {
+      if (error) {
+        reject(error);
+        return;
+      }
+      resolve();
+    });
+  });
+}
diff --git a/packages/server/src/server/hub/relationship-remote.ts b/packages/server/src/server/hub/relationship-remote.ts
index d0ae01089d..9c6f88a63d 100644
--- a/packages/server/src/server/hub/relationship-remote.ts
+++ b/packages/server/src/server/hub/relationship-remote.ts
@@ -2,6 +2,9 @@ import { WebSocket } from "ws";
 import { z } from "zod";
 import type { WebSocketLike } from "../websocket-server.js";
 
+const SOCKET_PING_INTERVAL_MS = 10_000;
+const SOCKET_PONG_TIMEOUT_MS = 45_000;
+
 export interface HubEnrollment {
   daemonId: string;
   idempotencyKey: string;
@@ -171,13 +174,42 @@ export class DirectHubRelationshipRemote implements HubRelationshipRemote {
       },
     });
     let settled = false;
+    let heartbeat: ReturnType<typeof setInterval> | undefined;
+    const stopHeartbeat = () => {
+      clearInterval(heartbeat);
+      heartbeat = undefined;
+    };
+    const fail = (error: Error) => {
+      if (settled) return;
+      settled = true;
+      stopHeartbeat();
+      socket.terminate();
+      events.failed(error);
+    };
+    let lastPongAt = 0;
+    socket.on("pong", () => {
+      lastPongAt = Date.now();
+    });
     socket.once("upgrade", (response) => {
       if (response.headers["x-paseo-session-protocol"] === "1") {
         sessionProtocol = "session-v1";
       }
     });
     socket.once("open", () => {
-      if (!settled) events.connected(socket as WebSocketLike, sessionProtocol);
+      if (settled) return;
+      lastPongAt = Date.now();
+      heartbeat = setInterval(() => {
+        if (socket.readyState !== WebSocket.OPEN) return;
+        if (Date.now() - lastPongAt >= SOCKET_PONG_TIMEOUT_MS) {
+          fail(new Error("Hub WebSocket heartbeat timed out"));
+          return;
+        }
+        socket.ping(undefined, undefined, (error) => {
+          if (error) fail(error);
+        });
+      }, SOCKET_PING_INTERVAL_MS);
+      heartbeat.unref?.();
+      events.connected(socket as WebSocketLike, sessionProtocol);
     });
     socket.once("unexpected-response", (_request, response) => {
       if (settled) {
@@ -194,16 +226,12 @@ export class DirectHubRelationshipRemote implements HubRelationshipRemote {
       events.closed(1006);
     });
     socket.once("close", (code) => {
+      stopHeartbeat();
       if (settled) return;
       settled = true;
       events.closed(code);
     });
-    socket.once("error", (error) => {
-      if (settled) return;
-      settled = true;
-      socket.terminate();
-      events.failed(error);
-    });
+    socket.once("error", fail);
     return socket;
   }