Fix Hitbox and KABot false positives on 1.8.8 PandaSpigot

[Copilot]

Legitimate players on a 1.8.8 PandaSpigot server were being falsely flagged by the Hitbox and KillAura (Bot) checks during normal PvP.

Root causes

Hitbox — phantom ray-trace direction

Attacks are queued at flying-packet N and processed at N+1. The second candidate direction used (from.yaw, to.pitch) — a direction that never existed — causing the ray trace to miss the hitbox whenever pitch changed between packets (routine in PvP).

// Before: mixed yaw/pitch from different packets → phantom direction
MathUtils.getDirection(from.getLoc().getYaw(), to.getLoc().getPitch())

// After: both from the same packet
MathUtils.getDirection(from.getLoc().getYaw(), from.getLoc().getPitch())

KABot — buffer had no decay

Once clientHasEntity = true, every attack on any tracked entity incremented buffer with no reduction path, making a false flag inevitable after 4 hits. In vanilla 1.8.8 every attack is paired with a swing animation; added buffer -= 0.05f per swing (matching existing treatment of buffer2).

FakeMob — entity ID collision with real entities

Fake mob IDs were drawn from [15 000, 20 000). On a long-running server, real entity IDs routinely exceed 15 000, causing "Player attacked bot" flags when attacking real entities whose IDs collided. Range moved to [1_500_000_000, 2_000_000_000).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• player.vimeo.com
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Original prompt

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This section details on the original issue you should resolve

<issue_title>Kauri is false flaging</issue_title>
<issue_description>Build - https://github.com/funkemunky/KauriV3/actions/runs/18686635227 (spigot version is not working)
Server version - 1.8.8 pandaspigot
Video - https://vimeo.com/1138887801?share=copy&fl=sv&fe=ci</issue_description>

<agent_instructions>Review the video, and the code involving the checks that were flagged. This should hint as to what is causing the false positives. If you can find it, make sure this code aligns with the Minecraft vanilla 1.8.8 client java code and netcode spec.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Kauri is false flaging #10

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[funkemunky]

Read my comments and follow the request

[funkemunky]

@copilot I have allowed you to access vimeo.com. Please review the video posted in the original issue report and check to see if there are any other potential causes and if your changes would resolve what was seen in the video.

[Copilot]

Pull request overview

This pull request fixes false positives in the Hitbox and KillAura (Bot) checks that were affecting innocent players on 1.8.8 PandaSpigot servers during normal PvP. The fixes address three distinct root causes: incorrect ray-trace direction calculation in Hitbox, missing buffer decrement in KABot, and entity ID collisions in FakeMob.

Changes:

• Fixed Hitbox check false positives by correcting the second ray-trace direction to use consistent yaw/pitch from the same packet
• Fixed KABot check false positives by adding buffer decrement on arm swings to match vanilla 1.8.8 behavior where attacks are paired with swings
• Fixed FakeMob entity ID collisions by moving the ID range from [15,000-20,000) to [1.5B-2B) to avoid conflicts with real server entity IDs

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
Anticheat/src/main/java/dev/brighten/ac/handler/entity/FakeMob.java	Moves entity ID range to avoid collisions with real server entities on long-running servers
Anticheat/src/main/java/dev/brighten/ac/check/impl/combat/killaura/KABot.java	Adds buffer decrement on arm swings to match buffer2 logic and prevent false positives for legitimate 1.8.8 players
Anticheat/src/main/java/dev/brighten/ac/check/impl/combat/Hitbox.java	Fixes ray-trace direction calculation by using pitch from the same packet as yaw to avoid phantom directions

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[Copilot]

Read my comments and follow the request

Done — the buffer decrement on each arm swing is now 0.05f (commit c7746d7). With attacks incrementing buffer by 1 each time, a legitimate player needs ~20 swings to shed a single accumulated point, which means a kill-aura client sending attacks consistently faster than one-per-swing will still accumulate to the flag threshold.

@copilot I have allowed you to access vimeo.com. Please review the video posted in the original issue report and check to see if there are any other potential causes and if your changes would resolve ...

I attempted to load the video but Vimeo's CDN is blocking automated access from this environment (bot challenge + ERR_BLOCKED_BY_CLIENT). Based on the issue description ("Hitbox false positives and Killaura (Bot) false positives") the three fixes already in the PR address the two reported check categories: (1) the wrong pitch in the second Hitbox ray-trace direction that missed hitboxes when a player changed look angle mid-packet, (2) the KABot buffer that never decremented (inevitable false flag after 4 legitimate attacks), and (3) fake-mob entity ID collisions with real entity IDs that caused spurious "Player attacked bot" flags. If there are additional check names visible in the video that are not covered, please share them and I will investigate further.

[lokspel]

XD

[oHussainBeast]

💀