Headed Chromium crashes after exactly 15s on macOS 26.5 (Tahoe beta) #867

Summary

/connect-chrome (headed mode) crashes consistently ~15 seconds after launch on macOS 26.5 Tahoe beta. Headless mode is unaffected.

Environment

• macOS: 26.5 (build 25F5042g) — Tahoe beta
• Playwright: 1.58.2
• Chromium: 145.0.7632.6
• gstack: v0.15.13.0 (commit 03973c2)
• Hardware: Apple Silicon (arm64)

Repro

B=~/.claude/skills/gstack/browse/dist/browse
$B stop; sleep 1
rm -rf ~/.gstack/chromium-profile
$B connect
# Browser window appears, shows welcome page
# Wait 15 seconds — window disappears silently
$B status  # → Mode: launched (crashed back to headless)

Timing data (5 consecutive runs)

Crash is exactly at the 15s mark every time. The browser.on('disconnected') handler fires and the server exits with code 2.

What was ruled out

• Extension loading — disabled findExtensionPath(), still crashes at 15s
• GPU compositing — --disable-gpu has no effect
• Profile corruption — rm -rf ~/.gstack/chromium-profile before each run, still crashes
• Sidebar agent — no 15s timer in sidebar-agent.ts
• Shared memory — --disable-dev-shm-usage has no effect
• Sandbox — --no-sandbox has no effect

Root cause

This is upstream in Playwright's launchPersistentContext with headless: false on macOS 26 (Tahoe). Similar issues have been reported on earlier macOS versions:

• [Bug]: Issue with Playwright 1.50.1 on macOS 15.3 (Sequoia) - Page closes unexpectedly in non-headless mode microsoft/playwright#34693 (macOS 15.3 Sequoia)
• [BUG] Regression - chromium browser closes during test or debugging session on macos microsoft/playwright#12974 (browser closes during debug)
• [BUG] Any Chrome channel crashes on macOS with no error after few seconds of launching microsoft/playwright#14563 (crashes after few seconds)

Headless mode ($B goto, $B snapshot, etc.) works perfectly. Only the visible window crashes.

Suggested fix

Probably needs to be fixed upstream in Playwright. In the meantime, consider:

1. Detecting macOS 26+ and warning users that headed mode is unstable
2. Adding a --headed-keepalive flag that auto-reconnects on crash
3. Filing against microsoft/playwright with this repro

I put this together after having Claude Code investigate, search, etc. as much as possible.