Watchcat

Server-side anti-cheat for Paper 1.21.11. By @Az7car.

Website: https://watchcat.gg Discord: https://discord.gg/2hPbabJ9jP

Features

Combat Detection (53 checks)

• Killaura, AimAssist, Reach, Hitbox, AutoClicker, Triggerbot
• Velocity, AntiKnockback, Criticals, BowAimbot, AutoShield
• AutoTotem, AutoArmor, FastBow, MultiAura, ShieldBreaker
• MaceSwitch, NoSlow, FastEat, FastHeal, KeepSprint
• AimLock, Regen, SuperKnockback, WTap, Backtrack
• PitchLimit, NoMiss, InvisibleAim, ReachMulti, CPSLimit
• Delay, AutoBlock, Combo, DoubleHit, PerfectBlock
• ShieldBlock, AutoWeapon, AutoPot, AutoPearl
• ReachOverride, HitBoxOverride, NoHurtCam, AntiWeakness
• AntiHunger, NoFire, NoPush, SmoothAim, RageAura
• ClickPattern, TickShift, AutoSoup, AutoLeave

Movement Detection (44 checks)

• Speed, Fly, NoFall, Step, Jesus, Spider, Glide, HighJump
• BunnyHop, FastLadder, Phase, Blink, LongJump, ElytraFly
• BoatFly, NoWeb, Strafe, SafeWalk, EntitySpeed, Derp
• AntiVoid, Motion, Gravity, AirJump, FastFall, Collision
• Prediction, TimerBalance, TimerAccel, Swim, Ascension
• JumpCheck, VehicleSpeed, IceSpeed, SlimeBlock, WaterSpeed
• LavaSpeed, WallClimb, Clip, YPort, SpeedLimit
• AntiLevitation, DolphinJump, Sneak, PingSpoof, PacketDelay
• NoDrag, NoJumpDelay, SpeedField, EnderPearl, AutoWalk

World Detection (34 checks)

• Scaffold, FastPlace, InventoryMove, FastBreak, Nuker
• AirPlace, Tower, ChestStealer, BuildReach, NoSwing
• AutoFarm, AutoFish, AutoMine, InventoryActions, AutoTool
• BlockInteraction, FastConsume, GhostBlock, RotationPlace
• InstantMine, MultiTask, Direction, PacketOrder, RotationBreak
• BreakPattern, ChestAura, AutoRespawn, FastDoor, Surround
• PistonPush, AutoSign, AutoDoor, AutoBrew, AutoEnchant
• AutoAnvil, BoatGlitch, ContainerSort, AutoSmithing
• PickRange, ExpPickup

Mod & Injector Detection (87 checks)

• BrandDetector, PayloadProber, TickTimerAnalyzer, BadPackets
• Freecam, AntiAFK, Timer, MorePackets, InvalidInteract
• Disabler, SkinBlinker, SpinBot, HeadRoll, NoRotateSet
• Flight, AntiSwear, AntiFlood, AntiAd, Aimbot, GroundSpoof
• XRay, Baritone, AutoCrystal, AntiAntiXRay, OreBot
• NoRender, Trajectory, ClickTP, AntiInvis, Proxy
• AntiAntiCheat, ScreenShare, PluginDetector, ClientSpoof
• PacketMani, ForceOP, NoPitchLimit, AntiFirework
• ResourceSpoof, NameSpoof, NoAttackCooldown, AntiCactus
• AntiBerry, NoPortalOverlay, NoPumpkin, NoFireOverlay
• AntiFog, NoScoreboard, AntiPotion, CrashPayload, ESP
• Tracers, NoFov, NoBob, AntiBlind, TimeSpoof, AntiShield
• BookExploit, NoWeather, AntiWDL, SoundPos, PacketSpam
• AntiResourcePack, NoPotionLabel, AntiBot, Raid

Machine Learning Brain

• 32-dimension feature vector (rotation deltas, GCD, click variance, acceleration, packet rate, velocity std/mean/trend, pitch entropy, convergence)
• ONNX Runtime inference (in-JVM, no external dependencies)
• Isolation Forest anomaly detection blending with heuristic scores
• CSV training data export for offline model training

Punishment System

• Shadow flagging with configurable confidence thresholds
• Randomized ban wave execution (30min-6hr jitter)
• Severity-based duration tiers: 30 days to permanent
• Offense multiplier: 1st=1x, 2nd=2x, 3rd=4x, 4th+=permanent
• IP bans alongside UUID bans
• Unique 7-character alphanumeric appeal code per player
• Non-deterministic scheduling to blind cheat developers

Architecture

• Direct Netty pipeline injection (no ProtocolLib dependency)
• Fully asynchronous check execution (off-main-thread)
• 100% reflection-based, no Mojang-mapped dependencies
• Maven build, Java 21, Paper 1.21.11
• 218 checks total | 265+ Java files

Building

mvn clean package

Output JAR in target/watchcat-1.0.0.jar.

Configuration

Edit config.yml in the plugin data folder. Each check has:

• enabled - toggle
• severity - critical/high/medium/low (affects ban duration)
• weight - contribution to confidence score
• Check-specific thresholds

Commands

• /watchcat alerts or /watchdog alerts - toggle alert messages
• /watchcat stats or /watchdog stats - check performance statistics
• /watchcat profile or /watchdog profile - detailed check profiling
• /watchcat checks [category] or /watchdog checks [category] - list checks with status
• /watchcat player <name> or /watchdog player <name> - per-player check state
• /watchcat reason <player> <reason> or /watchdog reason <player> <reason> - ban a player with reason
• /watchcat reload or /watchdog reload - reload configuration
• /watchcat whitelist <check|all> <player> or /watchdog whitelist - exemption management
• /watchcat report <check> <player> or /watchdog report - report a false positive
• /watchcat banwave or /watchdog banwave - trigger manual ban wave

Dependencies

• Paper 1.21.11 (required)
• ONNX Runtime 1.26.0 (bundled via Maven shade plugin)
• Java 21 (required)

License

All rights reserved. Not for redistribution without permission.