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notebooklm-cookie-keepalive-cron-silent-failure-root-cause-a

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NotebookLM Cookie Keepalive Cron — Silent Failure Root Cause and Fix

NotebookLM Cookie Keepalive Cron — Silent Failure Root Cause and Fix

The NotebookLM cookie-refresh cron (every 8h) silently failed from day one due to a file permission bug, causing auth to expire after ~3 days of zero keepalive activity.

Root cause: cookie-refresh.sh used set -euo pipefail and wrote logs to /var/log/notebooklm-cookie-refresh.log. The claude user (UID 1002) has no write permission to /var/log/. The script crashed on line 14 (echo >> "$LOG") before the actual Python refresh ever executed. Every 8h cron run failed silently — cron daemon logged execution but the script exited immediately.

Fix applied (31-Mar-2026):

  1. Moved log path from /var/log/notebooklm-cookie-refresh.log to /opt/shared/notebooklm-config/cookie-refresh.log (directory owned by claude)
  2. Removed set -euo pipefail — a keepalive script must not crash on log write failures
  3. Added 2>/dev/null to log echo to prevent any stderr noise from blocking execution

Verification: Manual run of cookie-refresh.sh succeeded — 17 cookies sent, 6 refreshed from Google Set-Cookie headers, log written correctly, MCP container auto-restarted.

Key files:

  • Cron wrapper: /opt/shared/notebooklm-config/cookie-refresh.sh
  • Python refresh: /opt/shared/notebooklm-config/cookie-refresh.py
  • Storage: /opt/shared/notebooklm-config/storage_state.json
  • Log: /opt/shared/notebooklm-config/cookie-refresh.log

Lesson: Never use set -euo pipefail in keepalive/cron scripts where the primary function must execute regardless of logging failures. Log writes are secondary — the refresh is what matters.

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