Configuration

The three secrets (TARGET_URL, TELEGRAM_BOT_TOKEN, TELEGRAM_CHAT_ID) are in Getting started. Everything else is an environment variable in scripts/check.sh (override it in the workflow if needed):

Variable	Default	Meaning
PROBE_ATTEMPTS	2	Failed attempts required to call it down
PROBE_RETRY_DELAY	25	Seconds between attempts
PROBE_TIMEOUT	20	Per-attempt timeout in seconds
REALERT_SECONDS	3600	Reminder interval while down, in elapsed outage time
WORKFLOW_FILE	deadman.yml	Workflow whose run history is read as state

The probe schedule is the */10 cron in .github/workflows/deadman.yml. Tightening it does not reliably help: see How it works.