How ClifF Monitor Works

Full guide. Setup, alert codes, reminders, edge cases.

The idea

You set your phone to silent or Do Not Disturb during work, sleep, or focus time. That's good for almost everything except one case: a family emergency where someone really needs to reach you. ClifF Monitor fills that gap.

Pick a code word with the people you trust. They text you that code in an emergency. Your phone wakes up, rings loudly through silent mode, and shows the alert. You tap one button to acknowledge it — the alarm stops and your location goes back to whoever raised the alert.

Designed for offline operation. ClifF Monitor works on cellular signal alone. No internet, no accounts, no cloud servers. If SMS can reach your phone, the alert will fire.

First-time setup

Install and grant permissions

The app needs SMS receive, SMS send, and coarse location. The onboarding screen explains why each one is needed.

Grant Do Not Disturb access

The single most important step. Without DND access, alerts cannot ring when your phone is on silent. The status card on the home screen will be amber until this is granted — tap it to open the Android settings page.

Add trusted contacts in Settings

Only numbers you add can trigger alerts. Anyone else sending the same code word is ignored. This is a hard guardrail, not a preference.

Share your alert code

Tell your trusted contacts what to send. The default is URGMOM, URGDAD, or URG followed by any word.

Test it

Use the TEST button on the home screen to simulate an incoming alert from your own number. The phone should ring loudly and the screen should wake.

Alert codes

An alert is any SMS that:

Comes from a number in your trusted contacts list, AND
Contains the URG prefix followed by any word (URGMOM, URGDAD, URGSARAH, URG911, etc.)

Both conditions must be true. A trusted contact sending "what time is dinner" does not trigger an alert. A stranger sending "URGMOM" does not trigger an alert.

Custom keywords

You can configure additional code words in Settings. These behave the same way — trusted sender plus matching keyword equals alert.

The acknowledgement reply

When an alert fires, your phone rings, wakes, and shows a notification with one action button: I'm on my way. Tapping it does three things:

Silences the alarm immediately.
Reads your phone's last known location (cached only — no fresh GPS lookup, zero battery impact).
Sends a reply SMS in the format I'm on my way | <your name> | <location>.

Why "I'm on my way"? In an emergency, the person who raised the alert needs one thing first: confirmation that someone heard them. Silence is unbearable. "I'm on my way" is the universal acknowledgement — it answers "are you there?" with the most reassuring possible response, regardless of what you literally do next. Whether you're physically heading over, calling emergency services, or already on the phone with them, the sender knows their alert reached a real human who is now acting. The exact next step gets discussed in the follow-up call or SMS — the acknowledgement just buys those crucial first seconds of relief.

What happens to location

Location is best-effort. The acknowledgement always sends — whether or not coordinates are available. The location field has one of two values:

A Plus Code (Open Location Code) — e.g. 9F4FXW7G+8R. This means the phone had a recent cached fix.
Location NA — means no usable location was available at the moment you tapped. The SMS still goes out.

Any of the following result in "Location NA":

Location permission denied for ClifF Monitor
Location services turned off system-wide on the phone
Permission granted and services on, but no cached fix yet — e.g. just after a reboot, or you've been indoors with no GPS signal for a while

Why no fresh GPS lookup? A GPS module takes 10–60 seconds to get a fix and consumes meaningful battery. In an emergency that delay is too long — the priority is to acknowledge fast and silence the alarm. ClifF Monitor reads only the cached location your phone already knows about. If you're using Google Maps or any other app that periodically updates location, the cache will usually have a recent fix.

Android 8+ background restrictions

From Android 8 (Oreo) onwards, background apps are limited to a single location read every few minutes — even with permission granted. This matches ClifF Monitor's "cached only" approach perfectly: the app doesn't request fresh GPS in the background, so the restriction never bites. The trade-off is that on long-idle phones the cached value may be stale or absent, which is the third "Location NA" case above.

Scheduled reminders (ATTN)

Beyond emergencies, trusted contacts can also schedule timed reminders on your phone. Useful for medication reminders, pickup times, anything you want a loud nudge for.

Format: ATTN-30M take medication or ATTN-10:30 pick up groceries.

Format	Meaning
`ATTN-30M`	Fire reminder in 30 minutes
`ATTN-1H`	Fire reminder in 1 hour
`ATTN-10:30`	Fire reminder at 10:30 today (or tomorrow if past)
`ATTN-CANCEL`	Cancel all pending reminders

The contact gets an SMS back confirming the schedule. When the reminder fires, the phone rings just like an emergency alert — same loud-through-silent treatment. Tap "Done" to dismiss.

Pause vs Force-Stop

Two ways to silence the app temporarily. Only one of them works the way you'd expect.

Use Pause, not Force Stop. Force-stopping the app via Android Settings does not reliably silence it — Android automatically restarts the monitoring service when an SMS arrives, and the alert will fire. The in-app Pause is the only reliable way to silence alerts.

Action	Service running	Alert fires	History logged
Pause (in-app)	Yes	No	Yes (PAUSED)
Force Stop (Android Settings)	Auto-restarts on next SMS	Yes	Yes (normal)
Boot / OS kill	Auto-restarts on boot	Yes	Yes (normal)

This is intentional Android system behaviour — a safety app must not silently miss messages. ClifF Monitor is built around that guarantee. To temporarily silence alerts without missing messages, use the Pause button on the home screen.

What the home screen tells you

The signal indicator

The pulsing rings around the dot show the current state:

Green — everything is working. Alerts will fire normally.
Amber — something is degraded. Tap the status card to fix it (usually DND access or SMS permission).
Red — monitoring is paused. SMS messages are being logged but no alerts will fire.

Recent alerts

The last few alerts received are shown on the home screen with timestamp, sender (last 4 digits), and message. Tap "See all" for the full history. Alerts received while paused are logged with a PAUSED badge.

Permissions explained

SMS receive

Required to detect incoming alerts. ClifF Monitor is not your SMS app. It does not read your message history, does not access your inbox. Each incoming SMS is checked in memory against your configured patterns, then discarded. No SMS content is ever written to disk.

SMS send

Used in two cases: (1) sending the "I'm on my way" reply when you tap the action button, and (2) sending a confirmation SMS back when a trusted contact schedules an ATTN reminder. Replies go only to the original sender of the alert.

Coarse location

Used only when you tap "I'm on my way". The app reads the cached last-known location (no fresh GPS lookup, zero battery impact) and includes it as a Plus Code in the reply SMS. Location is not stored anywhere, not transmitted to any server, not used at any other time.

Other system permissions

The app uses standard Android permissions for waking the screen, ringing through silent mode, running in the background, restarting after device reboot, and posting notifications. None of these involve network access. See the privacy policy for the full list.

Common questions

Will this drain my battery?

No. The foreground service idles using almost no CPU. The location read on alert acknowledgement is cached-only, so no GPS module is woken up. The app makes zero network calls. Expected battery cost: well under 1% per day.

Does it work without internet?

Yes. SMS works on cellular signal alone. If your phone has bars, alerts will reach you. ClifF Monitor never touches the internet for anything.

What if my phone is dead or out of signal?

The alert is held by your carrier and delivered when the phone reconnects. At that point ClifF Monitor will fire the alarm normally. This is standard SMS behaviour.

Can people I haven't added trigger alerts?

No. Only numbers in your trusted contacts list can fire alerts. Anyone else sending the same code word is silently ignored.

Does it work alongside my normal SMS app?

Yes. ClifF Monitor doesn't replace anything. Your normal SMS app keeps working exactly as before. ClifF only listens for the specific URG pattern from trusted contacts.

What happens if I uninstall it?

All data is in the app's private storage, which Android removes on uninstall. Nothing remains on your device, nothing was ever stored elsewhere.