Summary

The browser backend spawns a new subprocess for each session and communicates via stdout/stdin pipes. This has several issues:

• Subprocess overhead — spawning a new process per session is slow (~500ms) and wastes memory for repeat interactions.
• Orphan cleanup — if the parent process crashes, browser subprocesses are left running indefinitely. No PID tracking or cleanup hook exists.
• Socket communication — a persistent daemon with Unix socket or TCP communication would be faster and more reliable than pipe-based IPC.
• Shadow DOM — the current snapshot implementation does not pierce shadow DOM boundaries, missing content in web components.

Why It Matters

Performance and resource leaks. Users report orphaned Chromium processes consuming RAM after agent sessions end. The subprocess model also adds latency to every browser interaction.

Suggested Approach

1. Refactor to a daemon model: a single long-lived browser manager process that accepts commands over a Unix domain socket.
2. Register atexit and signal handlers to kill child browser processes on parent exit.
3. Add a periodic health check that reaps zombie/orphan processes.
4. For shadow DOM: use Playwright's shadowRoot traversal in the snapshot walker to pierce open shadow roots.

Related Findings

Audit items #36, #53, #66, #67: process management and DOM traversal analysis.