How to Use the Mob Spawning Overlay to Debug a Farm

The mob spawning overlay highlights the exact blocks where mobs are allowed to spawn. It is the tool you reach for when a farm is not producing, because it shows you whether your spawning area is actually valid.

Turning it on and reading it

Enable the mob spawning overlay in the config. Blocks that meet the spawning conditions get highlighted, while invalid blocks stay normal. Walk over your farm platform and watch which blocks light up. If large sections are not highlighted, mobs cannot spawn there and your rates will suffer.

Fixing common problems

If a platform block is not highlighted, check its light level first, then check whether the block below it is a valid spawning surface and whether the space above has enough room. Remove anything blocking spawns, such as torches, carpets, or non-solid blocks, and re-check. For farms that rely on a specific floor material, confirm the highlighted area matches the floor you intended.

Comparing before and after

Take a mental snapshot of how much of the platform is highlighted, make one change, then look again. This before-and-after loop is the quickest way to isolate why a farm underperforms. Combine this overlay with the light overlay so you can see both the spawnable blocks and the reason any block is excluded.