MythicalAC

Server-side anticheat for Forge 1.20.1 and Paper 1.21.x. Its combat checks cover Reach, KillAura, look-angle, through-wall multi-target aura, AutoClicker CPS and aim-snap, and movement checks cover Fly and Speed. Build and inventory checks flag Nuker use and similar automation. Violations build up as a level that decays over time, so a single stray false positive fades instead of leading to punishment. Confirmed cheaters are rubber-banded, kicked or auto-banned, and kick counts are saved to disk, so three kicks produce a ban that survives relogs and restarts.

Server-side only: clients need nothing and vanilla players join without installing anything. The mod is a set of checks that send no packets of their own, so it cannot see client-side render hacks such as ESP, tracers or HUDs. For X-ray and freecam the mod uses cloaking: it hides real ores and storage behind fake ores and fake cave tunnels, and reveals a block only once the player's position is in range. Cloaking uses per-block updates, so new areas take a brief warm-up and add some bandwidth cost with many players. Installation means dropping the jar in the server's mods folder.