Server-side and client-side software that detects unauthorised modifications to the game client (cheats, hacks, exploits) and flags or kicks the offending player.
Anti-cheat lives at multiple layers: the engine's built-in protections, server-side validation of physics-impossible actions, and third-party detection tools (FiveM's anti-cheat, EAC for Rust, BattlEye for many shooters). Detection events are noisy on their own: a single anti-cheat flag may be a false positive, but a pattern across logs over time is rarely innocent. ServerOps Logs stores anti-cheat events as structured records so staff can query 'show me every WEAPON_KNIFE flag for player X in the last 30 days' instead of grepping plaintext.