LagDetective
**Lag Detective is a lightweight Fabric diagnostics mod for Minecraft that helps you quickly understand why your game or server is lagging — without installing heavy profilers or complex tools.
It provides real-time performance monitoring, clear lag classification, and easy-to-read reports through simple commands and an optional client dashboard.**
What Lag Detective Does:
Lag Detective helps answer questions like:
- Is the lag coming from the server TPS or the client FPS?
- Are you CPU/tick bound, GPU/render bound, or memory/GC stuttering?
- Are too many entities loaded in one chunk?
- Is chunk loading or world generation causing spikes?
- What are the most likely causes right now?
Key Features:
Server Performance Tools:
- TPS and MSPT monitoring
- Entity and chunk activity tracking
- Server-side lag diagnosis
- Support report generation
Client Diagnostics Dashboard
- FPS + frame time monitoring
- Client tick time measurement
- Memory + GC spike detection
- Server metrics shown when available
Commands:
/ld status — server performance summary
/ld fps — current client FPS
/ld mspt — server tick time
/ld tps — server TPS estimate
/ld clientinfo — full client debug info
/ld serverinfo — full server debug info
/ld entity — chunk-by-chunk entity scan
/ld report — generate support report
/ld ui — open the diagnostics dashboard
Support Reports
Lag Detective can generate a complete diagnostic report for debugging or support requests:
- System + mod info
- Current TPS/FPS/MSPT
- Top lag causes with confidence scores
- Recommended actions
- Saved automatically as:
lagdetective-report.txt
Designed for Safety & Compatibility
- Works on client + dedicated server
- No mixins required
- Lightweight sampling (default once per second)
- Never modifies other mods or game settings
- Suggestions are informational only
Perfect For:
- Server owners tracking TPS drops
- Modpack developers diagnosing performance
- Players experiencing stutters or frame lag
- Debugging mob farms, chunk loaders, or heavy mods
