Mojang Dev Tools

Mojang Dev Tools

Unlocks the Mojang Development tools, useful for mod devs and players looking to understand more about the game!

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32 Downloads
fabricgame-mechanicsutilityworldgen
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Screenshots

Example of Mob Brain and Villager Pathing debug

About this Mod

Mojang Dev Tools

Brain and Path Example

Unlocks all hidden developer features normally only available inside Mojang's IDE — with an in-game config menu to toggle each flag individually. ALL TOOLS EXIST IN OFFICIALLY RELEASED MOJANG BINARIES, THIS MOD SIMPLY ENABLES THE FLAGS

Sets SharedConstants.IS_RUNNING_IN_IDE = true and MC_DEBUG_HOTKEYS=true at class-load time, enabling debug overlays, internal commands, and dev-mode keybinds that are shipped in the game but never exposed in production.


Requirements

  • Minecraft 26.1.2
  • Fabric Loader 0.19.2 or later

Key Features

Debug Keybinds (F3 held)

Hotkey Action
F3 + Z Custom debug renderer menu
F3 + F6 Mojang internal debug options menu
F3 + E Chunk section path debug overlay
F3 + F Toggle fog rendering
F3 + L Toggle smart culling
F3 + O Frustum culling octree overlay
F3 + U Freeze/capture frustum at current position
F3 + V Chunk section visibility overlay
F3 + W Wireframe rendering mode

Note: F3+F with this mod enabled toggles fog instead of cycling render distance — this is the dev-mode override.


Renderer Overlays

Toggle any of these in-game via F3 + F6:

  • Pathfinding route overlay
  • Block neighbor update overlay
  • Structure bounding box overlay
  • Mob brain & memory overlay
  • AI goal selector overlay
  • Point of interest (POI) overlay
  • Bee hive/path overlay
  • Raid state overlay
  • Village section overlay
  • Entity hitbox overlay (integrated server)
  • Block collision shape overlay
  • Sculk catalyst spread overlay
  • Breeze mob debug overlay
  • Experimental redstone wire update order overlay

World Generation Debug

  • Cave carver volume overlay
  • Ore vein bounds and type overlay
  • Aquifer cell boundary overlay
  • Per-chunk feature placement count heatmap
  • Large dripstone cluster overlay
  • Disable individual world gen passes (fluids, aquifers, surface, carvers, structures, features, ore veins, blending, retrogeneration)

Gameplay & QOL Flags

  • All villager trade tiers unlocked immediately
  • Ignore mob cap on integrated server
  • Open worlds from incompatible versions
  • Allow simulation distance below the normal minimum
  • Keep jigsaw blocks after structure generation
  • Structure edit mode
  • Save structures as SNBT text files
  • Per-tick timing monitor
  • Show all sound subtitles
  • Suppress outbound Mojang telemetry
  • Cursor position in F3 overlay
  • Suppress all world saves (world reverts on exit)

Internal Server Commands

Unlocked when IS_RUNNING_IN_IDE is active:

  • /raid — Force-start/stop raids, set omen level, spawn raid captains, toggle raider glow
  • /debugpath to <x> <y> <z> — Visualize pathfinding routes in-world
  • /debugmobspawning at <x> <y> <z> — Diagnose mob spawning per category
  • /warden_spawn_tracker — Read/write warden warning levels for nearby players
  • /spawn_armor_trims — Spawn all armor trim combinations on armor stands
  • /serverpack push/pop — Push/pop server resource packs to clients without restarting
  • /chase — Sync camera between two game instances (Mojang QA tool)

Available Versions

DevFlags 1.1.5release
MC 26.1.2fabric
May 29, 2026

How to Install Mojang Dev Tools on Your Server

1

Order Server

Order a Minecraft Java server with at least 4 GB RAM (6 GB recommended).

2

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (26.1.2).

3

Install Mod

Open the mod browser in the dashboard and search for "Mojang Dev Tools". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

fabric

Minecraft Versions

26.1.2

Server-side

Unsupported

Recommended RAM

6 GB(min. 4 GB)

Frequently Asked Questions

Mojang Dev Tools server crashes on startup – what to do?

Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 4 GB RAM is allocated and the loader matches the mod version (26.1.2). You can switch loaders with one click in the panel.

Is Mojang Dev Tools compatible with fabric?

Mojang Dev Tools officially supports fabric for Minecraft 26.1.2. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Mojang Dev Tools – how to optimize performance?

Recommended RAM: 6 GB (per 5 players). Use /spark profiler to check if Mojang Dev Tools consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

Rent Modded Server

Install Mojang Dev Tools with just one click on your server.

Recommended RAM
6 GBab €12/mo
Min. 4 GB | +1 GB pro 5 Spieler
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NVMe SSD Storage
DDoS Protection included

Details

License
GNU General Public License v3.0 or later
Server-side
Unsupported

Supported Versions

26.1.2