Entity ID Monitor

The game gives every spawned entity a number taken from one global integer that only increases. Entity ID Monitor reads that counter and draws it as a persistent overlay: the current value, the rate of new entities per second measured against wall-clock time so tick rate does not distort it, the number of IDs remaining before a configured threshold such as 1,000,000, and an estimated time until that threshold at the current rate. The overlay shows a mode (server or singleplayer) and an armed status, and its color shifts from white to yellow with a pulse as the counter nears the threshold, within a configurable alert distance.

The mod suits people studying how entities behave, profiling farms that produce large numbers of mobs, or doing low-level entity research, since most players never need the number. Its optional arming feature right-clicks the crosshair target once the counter hits the threshold, and a sound plays on entering the alert range. Automation and debugging tools are included, along with Entity ID Suppression for testing entity creation, and they are opt-in and never run unless armed. The overlay still works when setcounter or collide debugging is unavailable.

Both the server and every player need the mod for full accuracy: with it installed on both sides, the server syncs the real Entity.CURRENT ID value to connected clients. Where the server does not run the mod, clients use an estimate built from the largest entity ID they have seen. Entity ID Monitor requires Fabric API, and Cloth Config API and Mod Menu are optional. The code is open source under the MIT License, with a public source repository and an issue tracker, and it is published for Fabric and 1.21.11 only.