Background monitors

Set a condition like "alert me if /odom drops below 10 Hz" — Scry watches in the background and fires an alert into chat the moment the condition trips.

How to set one

Just ask the agent:

Watch /odom and alert me if its rate drops below 10 Hz.

The agent calls the monitor_threshold phone-side meta-tool with the right parameters. You'll see a confirmation in chat ("Monitor armed: /odom rate < 10 Hz"). The monitor is now live.

You can also set monitors on:

• Topic message field values — "alert me if /battery_state.percentage drops below 20"
• Topic publish rates — as above
• Service availability — "alert me if /global_costmap/clear_entirely_global_costmap becomes unavailable"
• Node liveness — "alert me if /navigation_lifecycle_manager dies"

Edge-triggered, not level-triggered

Monitors fire once per false-to-true transition, not continuously. If your battery drops to 19% the monitor fires; it does not keep firing every second while battery stays at 19%. Re-fires when battery goes above the threshold and then back below.

This matches what you actually want: notifications when something changed, not a stream of "still bad."

Where alerts show up

When a monitor trips, an assistant message appears in chat:

Note: Monitor fired: /odom rate < 10 Hz — current value 7.4 Hz

[robot context excerpt]

It looks identical to a regular assistant reply (same alignment, same brand mark). Difference is the Note: glyph and the explicit "Monitor fired" prefix.

The agent then sees this message on the next turn, so you can ask follow-ups like "what's causing the rate drop?" and it'll have full context.

Where monitors run

Monitors are app-scoped, not robot-scoped:

• MonitorRegistry is a Hilt @Singleton with SupervisorJob + Dispatchers.Default
• Each monitor opens an SSE subscription to the connect's /stream?topic=…
• The phone evaluates the predicate on each delta
• Process death cancels all monitors — they don't survive an app restart

That last point matters: monitors are good for "I'm using the app right now and don't want to miss this." They're not a substitute for a proper alerting system on the robot.

Listing and stopping monitors

In chat:

list my active monitors

The agent calls monitor_list which returns active monitors with their IDs, conditions, and current values. The reply renders as a chip strip above the composer with a Stop button on each chip.

You can also tell the agent:

stop the /odom monitor

And it'll call cancel_monitor for you.

Notifications when the app is backgrounded

Monitors keep running even when Scry is in the background or your screen is off. When one trips, you get:

1. A standard Android notification (requires the Notifications permission)
2. The chat message appears in app on next foreground

The notification is just "Monitor fired on [robot name]" — tap it to open Scry directly to the chat where the alert landed.