Combat Logger

By
KhadusGrinder

A client sided hack detection mod.

CombatLogger

Client-side combat analysis and hack detection for Minecraft 1.16.5.

Real-time combat telemetry, accurate reach estimation, threat scoring, packet inspection, and detailed session analysis — all running directly on your client.

**Analyze · Detect · Review**

Overview

CombatLogger is a client-side combat analysis mod designed to give you detailed information about what's happening during PvP.

Instead of relying on simple distance checks or raw client positions, CombatLogger combines server-tick timing, interpolated entity positions, latency data, attack patterns, movement analysis, and packet activity to build a more complete picture of combat.

It provides information in real time through an in-game HUD and keeps detailed logs that can be reviewed after a fight.

[!IMPORTANT] CombatLogger is an analysis tool, not a guaranteed anti-cheat. Detection results should be treated as indicators for investigation rather than definitive proof of cheating.

Features

Real-Time Combat HUD

Get important combat information without leaving the game.

┌─────────────────────────────────────────────┐
│ COMBAT              48ms    3.2m            │
│ LOG                                        │
├─────────────────────────────────────────────┤
│ [red dot] PlayerName              Diamond S │
│  -4.0hp   12 CPS            3.42 +/-0.35   │
│  ■■■■■■■■■■□□□□□□□□□  │ SUSPICIOUS │ x2 ↑ │
└─────────────────────────────────────────────┘

The HUD can display:

Target who last hit you
Damage dealt
Estimated reach
Attacker CPS
Ping
Threat level
Detection verdict
Weapon information

HUD position, scale, width, opacity, and other display options can be customized.

Reach Analysis

CombatLogger doesn't simply calculate the distance between two players' current client-side positions.

When an attack occurs, the mod uses interpolated entity positions and server tick timing to estimate where the players were positioned at the time of the attack.

This allows the reach calculation to account for the difference between:

Current client position
Interpolated entity position
Server tick timing
Network latency
Attack timing

The result is a more useful reach estimate than a simple raw-distance check.

Ping-Adjusted Reach

Network latency can introduce uncertainty into combat measurements.

CombatLogger accounts for the attacker's latency when determining the expected reach range.

This helps reduce false positives caused by:

High ping
Position updates arriving late
Client/server synchronization differences
Normal network jitter

Rather than treating every player identically, the analysis takes network conditions into consideration.

Threat Scoring

Every analyzed hit receives a 0–100 threat score.

The scoring system considers multiple signals instead of relying on a single detection.

Detection Signals

Signal	Description
Reach	How far beyond the expected range the hit appears to be
Hit Clustering	Unusually close or repeated attack timings
Airborne Attacks	Suspicious attack behavior while airborne
Damage Pattern	Unusual or inconsistent damage behavior
CPS	Attacker click rate and attack frequency
Movement	Abnormal vertical or positional movement

Threat Levels

Score	Level	Meaning
`0–14`	LOW	Little or no suspicious activity
`15–39`	MEDIUM	Some unusual behavior detected
`40–69`	HIGH	Multiple suspicious signals detected
`70–100`	CRITICAL	Strong combination of suspicious signals

The score is intended to help identify patterns — not to automatically declare a player guilty.

CPS Tracking

CombatLogger maintains a rolling CPS measurement for attackers during combat.

It also tracks attack timing to identify unusually tight clusters.

For example:

Attack intervals:

142 ms ── 118 ms ── 105 ms ── 47 ms ── 43 ms ── 49 ms
                                      └──── cluster ────┘

Extremely short intervals, including attacks occurring within approximately 50 ms, can contribute to the overall analysis.

Fly Detection

CombatLogger monitors vertical player movement to identify potentially abnormal movement patterns.

The system can flag unusual vertical movement that may be associated with:

Fly hacks
Abnormal movement
Movement exploits
Certain feather-fall-related anomalies

Movement analysis is treated as one signal among many rather than a standalone detection.

Packet Inspection

CombatLogger includes a packet monitoring system capable of inspecting client/server traffic relevant to combat analysis.

It can monitor packet rates and identify potential anomalies such as:

Attack packets
      │
      ├── Normal rate
      │
      ├── Unusual burst
      │
      └── Potential attack spam

Potential packet anomalies include:

Attack packet spam
Position packet flooding
Unusual packet bursts
Excessive position updates

This can provide additional context when normal combat analysis isn't enough.

Session Logging

CombatLogger keeps a detailed record of combat events throughout a session.

A logged hit can contain information such as:

Timestamp
Attacker
Weapon
Reach
Damage
CPS
Ping
Verdict
Threat Level

Example:

[18:42:31.452] HIT by ExamplePlayer | Weapon: Diamond Sword | Reach: 3.47m +/-0.35m | Damage: -4.0 | CPS: 12 | Ping: 52ms | MaxReach: 3.25m | Verdict: SUSPICIOUS | Threat: HIGH(64) | CLUSTERx2 | SPRINTING

This makes it possible to investigate fights after they happen instead of relying entirely on what was visible in-game.

Session Summary

When you disconnect, CombatLogger can generate a summary of the session.

The summary includes statistics such as:

Per-attacker threat scores
Reach consistency
Reach standard deviation
Average measurement uncertainty
Attack statistics
Detection results

This makes it easier to identify players who repeatedly produce suspicious results rather than focusing on a single hit.

Commands

Command	Description
`/cl hack`	Toggle hack detection and packet inspection
`/cl reach`	Display the latest reach estimation and verdict
`/cl log`	Display the current session log path
`/cl config`	Open the configuration screen
`/cl hud <x/y> <value>`	Change the HUD X or Y position
`/cl help`	Display all available commands

Configuration

Open the configuration screen in-game by pressing:

Right Shift

Available Options

Setting	Description
HUD Position	Change the location of the combat HUD
HUD Scale	Adjust the size of the HUD
HUD Width	Change the HUD's display width
Background Opacity	Adjust the HUD background transparency
Text Color	Customize text using RGB values
Hack Detection Panel	Enable or disable detection information
Weapon Display	Show or hide weapon information

Configuration is stored at:

config/combatlogger.json

Compatibility

Component	Version
Minecraft	`1.16.5`
Mod Loader	`Fabric`
Dependency	`Fabric API`
Installation	Client-side

[!NOTE] CombatLogger does not require a server-side installation.

How It Works

At a high level, CombatLogger processes combat events through several stages:

                 ┌─────────────────┐
                 │  Combat Event   │
                 └────────┬────────┘
                          │
                          ▼
                ┌───────────────────┐
                │ Position Analysis │
                └─────────┬─────────┘
                          │
                          ▼
                ┌───────────────────┐
                │  Reach Estimation │
                └─────────┬─────────┘
                          │
              ┌───────────┼───────────┐
              ▼           ▼           ▼
          ┌───────┐   ┌───────┐   ┌────────┐
          │  CPS  │   │ Ping  │   │ Packet │
          │ Track │   │Adjust │   │Analysis│
          └───┬───┘   └───┬───┘   └───┬────┘
              │           │           │
              └───────────┼───────────┘
                          ▼
                 ┌─────────────────┐
                 │ Threat Scoring  │
                 └────────┬────────┘
                          │
                 ┌────────┴────────┐
                 ▼                 ▼
           ┌───────────┐     ┌───────────┐
           │    HUD    │     │ Session   │
           │  Display  │     │   Log     │
           └───────────┘     └───────────┘

The purpose of this approach is to combine multiple pieces of information instead of making decisions from a single measurement.

Detection Disclaimer

[!WARNING] CombatLogger should not be treated as an authoritative anti-cheat system.

Combat analysis can be affected by many factors, including:

Network latency
Server tick rate
Interpolation
Knockback
Connection instability
Server-specific mechanics
Unusual movement behavior
Client/server synchronization

A suspicious result does not necessarily mean that a player is cheating.

CombatLogger is intended to provide evidence, statistics, and useful signals that can help with manual investigation.

Project Goals

CombatLogger is built around a few simple goals:

Accurate — Use server-tick-aware positioning instead of simple client distance.
Informative — Show useful combat information while you're playing.
Transparent — Provide the data behind suspicious results.
Lightweight — Keep analysis client-side without requiring server changes.
Reviewable — Store enough information to investigate a fight afterward.

Installation

Install Fabric Loader for Minecraft 1.16.5.
Install the required version of Fabric API.
Place the CombatLogger .jar file into your mods folder.
Launch Minecraft using your Fabric profile.
Join a server and press Right Shift to configure the mod.

Project Status

CombatLogger is an actively developed project. Detection behavior, scoring, and analysis may change as the system is improved and additional edge cases are handled.

If you find inaccurate detections or unexpected behavior, providing the relevant session logs and circumstances can help improve the analysis.