fix(cli): capture works inside an agent's macOS sandbox (#5840)

The seatbelt launch runs Chrome as one process, where there is no GPU process
to composite. Capture's flags left GPU compositing on, so every screenshot
failed and heavier pages stalled until the protocol timeout. The one-process
launch now also disables GPU compositing, as software capture already does.

Author: miguel-heygen

packages/cli/src/browser/launch.noListen.test.ts

@@ -30,7 +30,7 @@ describe("the GPU probe where nothing may listen", () => {
     await resolveManagedGpuMode("auto", "/chrome");
     expect(probe.options[0]).toMatchObject({
       pipe: true,
-      args: ["--headless", "--single-process"],
+      args: ["--headless", "--single-process", "--disable-gpu-compositing"],
     });
     expect(probe.options[1]!.pipe).toBeUndefined();
     expect(probe.options[1]!.args).toEqual(["--headless"]);

packages/cli/src/browser/sandboxDenied.test.ts

@@ -58,15 +58,22 @@ describe("a browser inside an agent's macOS seatbelt", () => {
     const { puppeteer, launches } = recordingPuppeteer([]);
     await launchManagedBrowser(puppeteer, { args: ["--headless"] });
     expect(launches).toHaveLength(1);
-    expect(launches[0]).toMatchObject({ pipe: true, args: ["--headless", "--single-process"] });
+    expect(launches[0]).toMatchObject({
+      pipe: true,
+      args: ["--headless", "--single-process", "--disable-gpu-compositing"],
+    });
   });
 
   it("relaunches as one process over a pipe when an unnamed sandbox refuses the mach service", async () => {
     vi.stubEnv("CODEX_SANDBOX", "");
     const { puppeteer, launches } = recordingPuppeteer([SEATBELT_LAUNCH_FAILURE]);
     await expect(launchManagedBrowser(puppeteer, { args: ["--headless"] })).resolves.toBeDefined();
     expect(launches.map((options) => options.pipe ?? false)).toEqual([false, true]);
-    expect(launches[1]!.args).toEqual(["--headless", "--single-process"]);
+    expect(launches[1]!.args).toEqual([
+      "--headless",
+      "--single-process",
+      "--disable-gpu-compositing",
+    ]);
   });
 });
 

packages/cli/src/browser/sandboxDenied.ts

@@ -2,6 +2,7 @@ import type { LaunchOptions } from "puppeteer-core";
 
 const MACH_SERVICE_DENIED = /bootstrap_check_in\b[^\n]*Permission denied/;
 const SINGLE_PROCESS = "--single-process";
+const CPU_COMPOSITING = "--disable-gpu-compositing";
 
 export function machServiceDenied(errorMessage: string): boolean {
   return MACH_SERVICE_DENIED.test(errorMessage);
@@ -12,14 +13,11 @@ export function inAgentSandbox(env = process.env, platform = process.platform):
   return platform === "darwin" && env.CODEX_SANDBOX === "seatbelt";
 }
 
-/** The one launch a seatbelt allows: no child process can register its mach port and nothing may listen. */
+/** The one launch a seatbelt allows: no child process registers a mach port, nothing listens, no GPU composites. */
 export function oneProcessOverPipe(options: LaunchOptions): LaunchOptions {
   const args = options.args ?? [];
-  return {
-    ...options,
-    pipe: true,
-    args: args.includes(SINGLE_PROCESS) ? args : [...args, SINGLE_PROCESS],
-  };
+  const missing = [SINGLE_PROCESS, CPU_COMPOSITING].filter((flag) => !args.includes(flag));
+  return { ...options, pipe: true, args: [...args, ...missing] };
 }
 
 export function isOneProcessOverPipe(options: LaunchOptions): boolean {

packages/cli/src/capture/captureCompositionFrame.browserFallback.test.ts

@@ -221,7 +221,11 @@ describe("openSettledCompositionPage when nothing may listen", () => {
       await openSettledCompositionPage(HTML, server.url, OPTIONS);
 
       expect(launched().pipe).toBe(true);
-      expect(launched().args).toEqual(["--headless", "--single-process"]);
+      expect(launched().args).toEqual([
+        "--headless",
+        "--single-process",
+        "--disable-gpu-compositing",
+      ]);
       expect(opened.page.setRequestInterception).toHaveBeenCalledWith(true);
       const onRequest = opened.page.on.mock.calls.find(([event]) => event === "request")![1];
       const respond = vi.fn(async (_response: { status: number; body: Buffer }) => undefined);