- Add AGENT_BROWSER_DEFAULT_TIMEOUT env var to override Playwright's
default 60s timeout (CDP/recording 10s timeouts unaffected)
- Add backpressure-aware safeWrite() that waits for drain when socket
buffer is full, preventing data loss under load
- Serialize command execution per socket via queue to prevent concurrent
writes that cause buffer contention
These daemon-side fixes complement #329 (CLI-side EAGAIN retry) by
addressing the root causes: Playwright operations that outlast the
CLI's IPC timeout, and concurrent socket.write() calls that overflow
the kernel buffer.
Tested with heavy React app (1000+ DOM nodes) — 10 consecutive
snapshot commands complete without os error 35/11.
Refs #322
Co-authored-by: shohu <shohu@users.noreply.github.com>
