gstack/browse
Garry Tan f42d7bac6d
feat(browse): terminal-agent watchdog with PID liveness + crash-loop guard
terminal-agent could die independently of the server — SIGKILL from the OS
OOM killer, an uncaught exception under PTY churn, an external `pkill` from
a sibling debugging session. Pre-v1.44 the sidebar would observe the broken
connection and stay broken until the user reloaded the sidebar. Now a 60s
ticker checks the recorded agent PID and respawns via the shared
spawnTerminalAgent helper when dead.

Identity-based liveness (T4 from the eng review):
  * Uses readAgentRecord + isProcessAlive (signal 0 probe), not a name match.
  * Slow-but-alive agents intentionally fall through — respawning around a
    living agent would create split-brain (two agents writing the port
    file, tokens diverging between them, mystery upgrade 401s).
  * Pairs with the v1.44 generation counter in /internal/* loopback calls:
    if a stale agent does come back to life mid-cycle, its X-Browse-Gen
    no longer matches and the parent's calls 409 cleanly.

Crash-loop guard:
  * 3 respawn attempts inside a rolling 60s window → stop trying. A daemon
    up for a week with one crash a day shouldn't trip the guard.
  * On trip: one-line error to console (`respawn guard tripped`) and the
    watchdog goes dormant. Manual restart via the sidebar Restart button
    is the explicit signal to re-arm (added in Commit 2 of the larger PR).

Shared spawn path (refactor):
  * New spawnTerminalAgent(opts) in terminal-agent-control.ts handles:
    prior-PID cleanup → spawn → record stash. Both the CLI cold-start path
    in cli.ts and the new server.ts watchdog route through it. Removes the
    copy-paste between them; future env wiring lands in one place.

Gated on cfg.ownsTerminalAgent — embedders that pre-launch their own PTY
server (gbrowser phoenix overlay) still own the full lifecycle.

GSTACK_AGENT_WATCHDOG_TICK_MS env knob compresses the 60s tick for e2e
tests without 60s waits per assertion.

Tests:
  * browse/test/terminal-agent-watchdog.test.ts — 7 static-grep tripwires
    for the load-bearing invariants (ownsTerminalAgent gate, PID-based
    liveness, crash-loop guard with window pruning, shutdown cleanup,
    CLI cold-start uses the same helper, env knob exists).
  * Live process-kill tests belong in the e2e tier; cheaper invariants
    here catch refactor regressions in ~1ms each.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-23 23:11:54 -07:00
..
bin feat: multi-agent support — gstack works on Codex, Gemini CLI, and Cursor (v0.9.0) (#226) 2026-03-19 18:20:50 -07:00
scripts fix: ngrok Windows build + close CI error-swallowing gap (v0.18.0.1) (#1024) 2026-04-16 13:49:04 -07:00
src feat(browse): terminal-agent watchdog with PID liveness + crash-loop guard 2026-05-23 23:11:54 -07:00
test feat(browse): terminal-agent watchdog with PID liveness + crash-loop guard 2026-05-23 23:11:54 -07:00
PLAN-snapshot-dropdown-interactive.md fix: snapshot -i auto-detects dropdown/popover interactive elements (#845) 2026-04-05 22:57:45 -07:00
SKILL.md v1.39.1.0 feat: EXIT PLAN MODE GATE for plan-mode review skills (#1512) 2026-05-15 08:13:20 -07:00
SKILL.md.tmpl v1.28.0.0 feat: browse --headed/--proxy/--navigate + gstack/llms.txt + webdriver-only stealth (#1363) 2026-05-07 20:14:59 -07:00