https://github.com/johnseth97/minecraft-dev-flag-fabric
Fabric mod that enables Minecraft dev/debug flags (IS_RUNNING_IN_IDE, MC_DEBUG_* properties) and adds an in-game toggle UI (F3+Z)
https://github.com/johnseth97/minecraft-dev-flag-fabric
Last synced: 15 days ago
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Fabric mod that enables Minecraft dev/debug flags (IS_RUNNING_IN_IDE, MC_DEBUG_* properties) and adds an in-game toggle UI (F3+Z)
- Host: GitHub
- URL: https://github.com/johnseth97/minecraft-dev-flag-fabric
- Owner: johnseth97
- Created: 2026-05-26T06:55:22.000Z (19 days ago)
- Default Branch: main
- Last Pushed: 2026-05-26T08:46:21.000Z (19 days ago)
- Last Synced: 2026-05-26T09:00:17.866Z (19 days ago)
- Language: Java
- Size: 2.7 MB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# devflags-fabric
Fabric mod for Minecraft 26.1.2 that unlocks all hidden developer features normally only available inside Mojang's IDE.
Sets `SharedConstants.IS_RUNNING_IN_IDE = true` and `MC_DEBUG_HOTKEYS=true` at class-load time.
---
## Important Keybinds
`F3 + Z` - Custom debug renderer menu
`F3 + F6` - Mojang internal debug options menu
## Server Commands
These commands are registered only when `IS_RUNNING_IN_IDE` is true. All require operator permissions at the level noted.
### `/raid` — Admin
Controls and inspects raid state. Requires a player to be in a valid raid region.
| Subcommand | Description |
|---|---|
| `start [omenlvl]` | Force-start a raid at your position with optional omen level |
| `stop` | Immediately end the active raid |
| `check` | Print current raid status to chat |
| `sound ` | Play a raid sound |
| `spawnleader` | Force-spawn a raid captain |
| `setomen ` | Override the current omen level |
| `glow` | Toggle glow on all active raiders |
### `/debugpath to ` — Gamemaster
Computes and visualizes the pathfinding route from your entity to the given block position. Renders the path in the world and reports whether the target is reachable.
### `/debugmobspawning at ` — Gamemaster
Forces the mob spawning evaluation at the specified position and prints the result for each spawn category. Useful for diagnosing why mobs are or aren't spawning.
### `/warden_spawn_tracker` — Gamemaster
Directly reads and writes the warden spawn tracker state for players in range.
| Subcommand | Description |
|---|---|
| `clear` | Reset the warning level for all nearby players |
| `set ` | Set warning level to 0–4 on all nearby players |
### `/spawn_armor_trims *_lag_my_game [pattern]` — Gamemaster
Spawns a complete set of armor stands wearing every armor trim combination (all materials × all patterns). The subcommand is intentionally named `*_lag_my_game` — this will tank FPS on large registries.
### `/serverpack push [uuid] [hash]` / `pop` — Gamemaster
Pushes a server resource pack URL to all connected clients, or pops the most recently pushed pack. Useful for testing pack delivery without restarting.
### `/debugconfig config ` / `unconfig ` — Admin (dedicated server only)
Sends or revokes a dialog config to a specific player by UUID. Used for testing the dialog/screen config system.
---
## Always-Available Commands
These are registered regardless of dev flags.
### `/chase` — Any op
Connects two game instances together so one follows another's camera. Intended for internal Mojang recording/QA sessions.
| Subcommand | Description |
|---|---|
| `lead [bind_address] [port]` | Start leading — other instances can follow you |
| `follow [port]` | Follow another instance's camera |
| `stop` | Disconnect |
### `/test` — Any op
Runs the built-in game test framework. Only `minecraft:always_pass` is present in the public jar — Mojang's internal test suite is not shipped.
```
/test run minecraft:always_pass
```
---
## Debug Hotkeys (Client)
All hotkeys below require F3 to be held. They are unlocked by `MC_DEBUG_HOTKEYS=true` and are handled by `handleChunkDebugKeys` inside `KeyboardHandler`.
> **Note:** F3+F with this mod enabled toggles fog instead of cycling render distance. This is the dev-mode override.
| Hotkey | Action |
|---|---|
| F3+E | Toggle chunk section path debug overlay |
| F3+F | Toggle fog rendering on/off |
| F3+L | Toggle smart culling (`Minecraft.smartCull`) |
| F3+O | Toggle frustum culling octree overlay |
| F3+U | Capture/freeze frustum at current camera position |
| F3+Shift+U | Kill (release) the captured frustum |
| F3+V | Toggle chunk section visibility overlay |
| F3+W | Toggle wireframe rendering mode |
### What frustum capture does
F3+U freezes the view frustum in place. The game continues rendering from your new camera position but only draws chunks/entities that were visible from where you pressed the key. This lets you fly around and observe exactly what the frustum culling algorithm sees.
---
## Bonus: Verbose Command Errors
With `IS_RUNNING_IN_IDE = true`, command execution errors print a full stack trace to chat rather than just the error message. Useful when writing or debugging datapacks and function files.
---
## Debug Flags Reference
### Renderer / Overlay Flags
| Property | Effect |
|---|---|
| `MC_DEBUG_ENABLED` | Master debug mode switch |
| `MC_DEBUG_HOTKEYS` | Enables F3+* chunk/render debug hotkeys |
| `MC_DEBUG_PATHFINDING` | Pathfinding route overlay |
| `MC_DEBUG_NEIGHBORSUPDATE` | Block neighbor update overlay |
| `MC_DEBUG_STRUCTURES` | Structure bounding box overlay |
| `MC_DEBUG_GAME_EVENT_LISTENERS` | Game event listener overlay |
| `MC_DEBUG_VILLAGE_SECTIONS` | Village section overlay |
| `MC_DEBUG_BRAIN` | Mob brain/memory overlay |
| `MC_DEBUG_POI` | Point of interest overlay |
| `MC_DEBUG_BEES` | Bee hive/path overlay |
| `MC_DEBUG_RAIDS` | Raid state overlay |
| `MC_DEBUG_GOAL_SELECTOR` | AI goal selector overlay |
| `MC_DEBUG_EXPERIMENTAL_REDSTONEWIRE_UPDATE_ORDER` | Experimental redstone wire update order overlay |
| `MC_DEBUG_SHAPES` | Block collision shape overlay |
| `MC_DEBUG_SHOW_LOCAL_SERVER_ENTITY_HIT_BOXES` | Entity hitbox overlay (integrated server) |
| `MC_DEBUG_ENTITY_BLOCK_INTERSECTION` | Entity/block intersection overlay |
| `MC_DEBUG_BLOCK_BREAK` | Block break progress overlay |
| `MC_DEBUG_BREEZE_MOB` | Breeze mob debug overlay |
| `MC_DEBUG_SCULK_CATALYST` | Sculk catalyst spread overlay |
| `MC_DEBUG_LARGE_DRIPSTONE` | Large dripstone generation overlay |
| `MC_DEBUG_CARVERS` | Cave carver debug overlay |
| `MC_DEBUG_ORE_VEINS` | Ore vein generation overlay |
| `MC_DEBUG_AQUIFERS` | Aquifer placement overlay |
| `MC_DEBUG_FEATURE_COUNT` | Feature placement count overlay |
### Gameplay / QOL Flags
| Property | Effect |
|---|---|
| `MC_DEBUG_DEV_COMMANDS` | Enables additional internal dev commands |
| `MC_DEBUG_VERBOSE_COMMAND_ERRORS` | Full stack traces on command errors in chat |
| `MC_DEBUG_UNLOCK_ALL_TRADES` | All villager trade tiers unlocked immediately |
| `MC_DEBUG_IGNORE_LOCAL_MOB_CAP` | Ignore mob cap on integrated server |
| `MC_DEBUG_OPEN_INCOMPATIBLE_WORLDS` | Allow opening worlds from incompatible versions |
| `MC_DEBUG_ALLOW_LOW_SIM_DISTANCE` | Allow simulation distance below the normal minimum |
| `MC_DEBUG_CHASE_COMMAND` | Enables `/chase` camera sync command |
| `MC_DEBUG_BYPASS_REALMS_VERSION_CHECK` | Skip Realms version compatibility check |
| `MC_DEBUG_TRIAL_SPAWNER_DETECTS_SHEEP_AS_PLAYERS` | Trial spawner treats sheep as players (activation testing) |
| `MC_DEBUG_VAULT_DETECTS_SHEEP_AS_PLAYERS` | Vault treats sheep as players (activation testing) |
| `MC_DEBUG_KEEP_JIGSAW_BLOCKS_DURING_STRUCTURE_GEN` | Keep jigsaw blocks in place after structure generation |
| `MC_DEBUG_STRUCTURE_EDIT_MODE` | Structure edit mode — preserves structure blocks in world |
| `MC_DEBUG_SAVE_STRUCTURES_AS_SNBT` | Save structures as SNBT text files instead of NBT |
| `MC_DEBUG_SHOW_SERVER_DEBUG_VALUES` | Show server-side debug values in F3 overlay |
| `MC_DEBUG_MONITOR_TICK_TIMES` | Record per-tick timing data |
| `MC_DEBUG_SUBTITLES` | Show subtitle entries for all sounds |
| `MC_DEBUG_CURSOR_POS` | Show cursor coordinates in F3 overlay |
| `MC_DEBUG_SOCIAL_INTERACTIONS` | Show social interaction debug info |
| `MC_DEBUG_WORLD_RECREATE` | Enable world recreation debug tooling |
| `MC_DEBUG_PANORAMA_SCREENSHOT` | Enable panorama screenshot capture mode |
| `MC_DEBUG_FORCE_ONBOARDING_SCREEN` | Always show the new-player onboarding screen on launch |
| `MC_DEBUG_DUMP_TEXTURE_ATLAS` | Dump texture atlases to disk on load |
| `MC_DEBUG_SYNCHRONOUS_GL_LOGS` | Emit GL debug logs synchronously |
| `MC_DEBUG_JFR_PROFILING_ENABLE_LEVEL_LOADING` | Enable JFR profiling during level load |
| `MC_DEBUG_VERBOSE_SERVER_EVENTS` | Log server events verbosely |
### Intentionally OFF (destructive / disruptive)
| Property | Why it's off |
|---|---|
| `MC_DEBUG_DONT_SAVE_WORLD` | World progress is never written to disk |
| `MC_DEBUG_CHAT_DISABLED` | Disables chat entirely |
| `MC_DEBUG_FORCE_TELEMETRY` | Forces telemetry submission |
| `MC_DEBUG_DISABLE_LIQUID_SPREADING` | Liquids freeze in place |
| `MC_DEBUG_DISABLE_FLUID_GENERATION` | No fluid generation during world gen |
| `MC_DEBUG_DISABLE_AQUIFERS` | Aquifers skipped during world gen |
| `MC_DEBUG_DISABLE_SURFACE` | Surface pass skipped during world gen |
| `MC_DEBUG_DISABLE_CARVERS` | Cave carvers skipped during world gen |
| `MC_DEBUG_DISABLE_STRUCTURES` | Structures skipped during world gen |
| `MC_DEBUG_DISABLE_FEATURES` | All features (trees, ores, etc.) skipped |
| `MC_DEBUG_DISABLE_ORE_VEINS` | Ore veins skipped during world gen |
| `MC_DEBUG_DISABLE_BLENDING` | Blending pass skipped during world gen |
| `MC_DEBUG_DISABLE_BELOW_ZERO_RETROGENERATION` | Below-zero retrogen skipped |
---
## Installation
**Requirements**
- Minecraft **26.1.2**
- [Fabric Loader](https://fabricmc.net/use/installer/) **0.19.2** or later
**Steps**
1. Download the latest `devflags-fabric-*.jar` from the [Releases](../../releases/latest) page.
2. Place the jar in your instance's `mods/` folder:
- **Prism Launcher** — right-click your instance → *Edit* → *Mods* → *Add from file*, or drop the jar into `/minecraft/mods/`
- **Default launcher** — `%APPDATA%\.minecraft\mods\` (Windows) or `~/.minecraft/mods/` (macOS/Linux)
3. Launch Minecraft. No configuration needed — all debug flags are enabled automatically on startup.
> While waiting for Modrinth approval, builds are only available via the Releases page above.
---
## Build
```
./gradlew build
```
Output: `build/libs/devflags-fabric-1.0.0.jar`
Copy to your instance's `minecraft/mods/` folder, or use the VS Code task (`Cmd+Shift+B`) which builds and deploys to the "26.1.2 Dev Flags Enabled" Prism instance automatically.