diff --git a/src/browser/extension-relay.test.ts b/src/browser/extension-relay.test.ts
index 8725c3f33e8..6a65e592c22 100644
--- a/src/browser/extension-relay.test.ts
+++ b/src/browser/extension-relay.test.ts
@@ -392,6 +392,53 @@ describe("chrome extension relay server", () => {
     ext2.close();
   });
 
+  it("keeps /json/version websocket endpoint during short extension disconnects", async () => {
+    const { port, ext } = await startRelayWithExtension();
+    ext.send(
+      JSON.stringify({
+        method: "forwardCDPEvent",
+        params: {
+          method: "Target.attachedToTarget",
+          params: {
+            sessionId: "cb-tab-disconnect",
+            targetInfo: {
+              targetId: "t-disconnect",
+              type: "page",
+              title: "Disconnect test",
+              url: "https://example.com",
+            },
+            waitingForDebugger: false,
+          },
+        },
+      }),
+    );
+
+    await waitForListMatch(
+      async () =>
+        (await fetch(`${cdpUrl}/json/list`, {
+          headers: relayAuthHeaders(cdpUrl),
+        }).then((r) => r.json())) as Array<{ id?: string }>,
+      (list) => list.some((entry) => entry.id === "t-disconnect"),
+    );
+
+    const extClosed = waitForClose(ext, 2_000);
+    ext.close();
+    await extClosed;
+
+    const version = (await fetch(`${cdpUrl}/json/version`, {
+      headers: relayAuthHeaders(cdpUrl),
+    }).then((r) => r.json())) as {
+      webSocketDebuggerUrl?: string;
+    };
+    expect(String(version.webSocketDebuggerUrl ?? "")).toContain("/cdp");
+
+    const cdp = new WebSocket(`ws://127.0.0.1:${port}/cdp`, {
+      headers: relayAuthHeaders(`ws://127.0.0.1:${port}/cdp`),
+    });
+    await waitForOpen(cdp);
+    cdp.close();
+  });
+
   it("waits briefly for extension reconnect before failing CDP commands", async () => {
     const { port, ext: ext1 } = await startRelayWithExtension();
     const cdp = new WebSocket(`ws://127.0.0.1:${port}/cdp`, {
diff --git a/src/browser/extension-relay.ts b/src/browser/extension-relay.ts
index 3f5697f1d56..a6f14091f6e 100644
--- a/src/browser/extension-relay.ts
+++ b/src/browser/extension-relay.ts
@@ -82,7 +82,7 @@ type ConnectedTarget = {
 };
 
 const RELAY_AUTH_HEADER = "x-openclaw-relay-token";
-const DEFAULT_EXTENSION_RECONNECT_GRACE_MS = 5_000;
+const DEFAULT_EXTENSION_RECONNECT_GRACE_MS = 20_000;
 const DEFAULT_EXTENSION_COMMAND_RECONNECT_WAIT_MS = 3_000;
 
 function headerValue(value: string | string[] | undefined): string | undefined {
@@ -256,6 +256,7 @@ export async function ensureChromeExtensionRelayServer(opts: {
     const cdpClients = new Set<WebSocket>();
     const connectedTargets = new Map<string, ConnectedTarget>();
     const extensionConnected = () => extensionWs?.readyState === WebSocket.OPEN;
+    const hasConnectedTargets = () => connectedTargets.size > 0;
     let extensionDisconnectCleanupTimer: NodeJS.Timeout | null = null;
     const extensionReconnectWaiters = new Set<(connected: boolean) => void>();
 
@@ -534,8 +535,9 @@ export async function ensureChromeExtensionRelayServer(opts: {
           Browser: "OpenClaw/extension-relay",
           "Protocol-Version": "1.3",
         };
-        // Only advertise the WS URL if a real extension is connected.
-        if (extensionConnected()) {
+        // Keep reporting CDP WS while attached targets are cached, so callers can
+        // reconnect through brief MV3 worker disconnects.
+        if (extensionConnected() || hasConnectedTargets()) {
           payload.webSocketDebuggerUrl = cdpWsUrl;
         }
         res.writeHead(200, { "Content-Type": "application/json" });
@@ -658,10 +660,8 @@ export async function ensureChromeExtensionRelayServer(opts: {
           rejectUpgrade(socket, 401, "Unauthorized");
           return;
         }
-        if (!extensionConnected()) {
-          rejectUpgrade(socket, 503, "Extension not connected");
-          return;
-        }
+        // Allow CDP clients to connect even during brief extension worker drops.
+        // Individual commands already wait briefly for extension reconnect.
         wssCdp.handleUpgrade(req, socket, head, (ws) => {
           wssCdp.emit("connection", ws, req);
         });