diff --git a/services/edge-broker/server.mjs b/services/edge-broker/server.mjs
index 81576304..7bd16008 100644
--- a/services/edge-broker/server.mjs
+++ b/services/edge-broker/server.mjs
@@ -254,16 +254,27 @@ export function createBrokerServer(options = {}) {
     }
   };
 
+  const closeBrowserShellSocket = (sessionRecord, reason, message = null, code = 1000) => {
+    sessionRecord.closedReason = reason;
+    if (sessionRecord.ws.readyState >= 2) {
+      return;
+    }
+
+    sendJson(sessionRecord.ws, {
+      type: "closed",
+      reason,
+      ...(message ? { message } : {}),
+    });
+    sessionRecord.ws.close(code, reason);
+  };
+
   const markGatewayShellSessionsClosed = (gatewayId, reason) => {
     for (const sessionRecord of browserShellSessions.values()) {
       if (String(sessionRecord.session.gateway_id) !== String(gatewayId)) {
         continue;
       }
 
-      sessionRecord.closedReason = reason;
-      if (sessionRecord.ws.readyState < 2) {
-        sessionRecord.ws.close();
-      }
+      closeBrowserShellSocket(sessionRecord, reason, "Gateway agent disconnected from the broker.", 1011);
     }
   };
 
@@ -448,6 +459,7 @@ export function createBrokerServer(options = {}) {
             closedReason: null,
           };
           browserShellSessions.set(String(session.id), sessionRecord);
+          wss.emit("connection", ws, req);
 
           const agent = agents.get(String(session.gateway_id));
           if (agent && agent.readyState === 1) {
@@ -464,10 +476,13 @@ export function createBrokerServer(options = {}) {
               },
             });
           } else {
-            sessionRecord.closedReason = "agent_offline";
-            ws.close();
+            closeBrowserShellSocket(
+              sessionRecord,
+              "agent_offline",
+              "Gateway agent is not connected to the broker.",
+              1011
+            );
           }
-          wss.emit("connection", ws, req);
         });
         return;
       }
@@ -624,11 +639,11 @@ export function createBrokerServer(options = {}) {
             }
 
             if (message.type === "SHELL_EXIT") {
-              sendJson(sessionRecord.ws, { type: "closed", code: message.code ?? 0 });
+              sendJson(sessionRecord.ws, { type: "closed", reason: "agent_exit", code: message.code ?? 0 });
               await closeBrowserShellSession(sessionRecord, "agent_exit");
               browserShellSessions.delete(String(message.sessionId));
               if (sessionRecord.ws.readyState < 2) {
-                sessionRecord.ws.close();
+                sessionRecord.ws.close(1000, "agent_exit");
               }
             }
           }
diff --git a/services/edge-broker/test/broker.test.mjs b/services/edge-broker/test/broker.test.mjs
index d005df47..78bb7e05 100644
--- a/services/edge-broker/test/broker.test.mjs
+++ b/services/edge-broker/test/broker.test.mjs
@@ -109,7 +109,7 @@ test("broker bridges browser shell sessions through the connected agent", async
 
   assert.ok(browserMessages.some((message) => message.type === "opened"));
   assert.ok(browserMessages.some((message) => message.type === "output" && /root@pi/.test(message.data)));
-  assert.ok(browserMessages.some((message) => message.type === "closed" && message.code === 0));
+  assert.ok(browserMessages.some((message) => message.type === "closed" && message.reason === "agent_exit" && message.code === 0));
   assert.equal(closedSessions.length, 1);
   assert.equal(closedSessions[0].reason, "agent_exit");
 
@@ -177,10 +177,19 @@ test("broker closes browser shell sessions immediately when no agent is connecte
   const port = address.port;
 
   const browser = new WebSocket(`ws://127.0.0.1:${port}/ws/browser-shell?token=session-token`);
+  const browserMessages = collectMessages(browser);
   await new Promise((resolve) => browser.once("open", resolve));
   await waitForClose(browser);
   await waitFor(() => closedSessions.length === 1, { description: "offline shell session close callback" });
 
+  assert.ok(
+    browserMessages.some(
+      (message) =>
+        message.type === "closed" &&
+        message.reason === "agent_offline" &&
+        /not connected to the broker/i.test(message.message)
+    )
+  );
   assert.deepEqual(closedSessions, [{ transcript: "", reason: "agent_offline" }]);
 
   await broker.close();
@@ -203,6 +212,7 @@ test("broker closes browser shell sessions when the agent disconnects before she
 
   const agentMessages = collectMessages(agent);
   const browser = new WebSocket(`ws://127.0.0.1:${port}/ws/browser-shell?token=session-token`);
+  const browserMessages = collectMessages(browser);
   await new Promise((resolve) => browser.once("open", resolve));
   await waitForMessage(agent);
 
@@ -211,6 +221,7 @@ test("broker closes browser shell sessions when the agent disconnects before she
   await waitFor(() => closedSessions.length === 1, { description: "disconnect shell session close callback" });
 
   assert.ok(agentMessages.some((message) => message.type === "OPEN_ROOT_SHELL" && message.payload.sessionId === "shell-4"));
+  assert.ok(browserMessages.some((message) => message.type === "closed" && message.reason === "agent_disconnected"));
   assert.deepEqual(closedSessions, [{ transcript: "", reason: "agent_disconnected" }]);
 
   await broker.close();