fix(browser): block node routes when sandbox host control is disabled (#97958)

extensions/browser/src/browser-tool.test.ts

@@ -871,6 +871,21 @@ describe("browser tool snapshot maxChars", () => {
     expect(browserClientMocks.browserStatus).not.toHaveBeenCalled();
   });
 
+  it.each([
+    ["target=node", { target: "node" }],
+    ["an explicit node pin", { node: "node-1" }],
+    ["automatic node routing", {}],
+  ])("blocks %s when host control is disabled", async (_label, route) => {
+    mockSingleBrowserProxyNode();
+    const tool = createBrowserTool({ allowHostControl: false });
+
+    await expect(tool.execute?.("call-1", { action: "status", ...route })).rejects.toThrow(
+      /browser control is disabled by sandbox policy/i,
+    );
+    expect(gatewayMocks.callGatewayTool).not.toHaveBeenCalled();
+    expect(browserClientMocks.browserStatus).not.toHaveBeenCalled();
+  });
+
   it("fails node proxy calls cleanly when payloadJSON is malformed", async () => {
     mockSingleBrowserProxyNode();
     gatewayMocks.callGatewayTool.mockResolvedValueOnce({
@@ -1247,7 +1262,7 @@ describe("browser tool snapshot maxChars", () => {
     setResolvedBrowserProfiles({
       user: { driver: "existing-session", attachOnly: true, color: "#00AA00" },
     });
-    const tool = createBrowserTool();
+    const tool = createBrowserTool({ allowHostControl: true });
     await tool.execute?.("call-1", { action: "status", profile: "user", target: "node" });
 
     const { options, request } = lastNodeInvokeCall();

extensions/browser/src/browser-tool.ts

@@ -262,7 +262,15 @@ async function resolveBrowserNodeTarget(params: {
   requestedNode?: string;
   target?: "sandbox" | "host" | "node";
   sandboxBridgeUrl?: string;
+  allowHostControl?: boolean;
 }): Promise<BrowserNodeTarget | null> {
+  if (params.allowHostControl === false) {
+    if (params.target === "node" || params.requestedNode) {
+      throw new Error("Node browser control is disabled by sandbox policy.");
+    }
+    return null;
+  }
+
   const cfg = browserToolDeps.getRuntimeConfig();
   const policy = cfg.gateway?.nodes?.browser;
   const mode = policy?.mode ?? "auto";
@@ -538,6 +546,7 @@ export function createBrowserTool(opts?: {
           requestedNode: requestedNode ?? undefined,
           target,
           sandboxBridgeUrl: opts?.sandboxBridgeUrl,
+          allowHostControl: opts?.allowHostControl,
         });
       } catch (error) {
         // Keep the logged-in user browser usable on the host when auto-discovery