Configurable Zombie AI

Configurable Zombie AI is a Minecraft Forge mod for 1.16.5 that makes vanilla zombies easier to tune for harder survival servers and modpacks.

Instead of hardcoding one zombie behavior profile, the mod exposes runtime commands for server operators so they can change how zombies detect, acquire, keep, and switch targets without restarting the world. Settings are stored with the world and apply to loaded zombies immediately.

What It Does

• Changes zombie follow range (configurable).
• Optionally lets zombies ignore line of sight checks.
• Optionally prevents zombies from despawning naturally.
• Replaces vanilla "pick the nearest valid target" behavior with configurable target acquisition.
• Optionally lets zombies re-evaluate and switch targets over time using weighted rules.
• Adds easy-to-use admin commands to kill zombies globally or within a radius.
• Works on both zombies, zombie villagers, and Pure Titans from the SNC Datapack.

The mod keeps vanilla target families intact. A zombie can still only target the kinds of entities vanilla would normally allow, but the selection logic inside those target pools becomes configurable.

Compatibility

• Minecraft: 1.16.5
• Forge: 36.x or newer in the 1.16.5 line
• Language/runtime: Kotlin via KotlinForForge
• Implementation details: Sponge Mixin injections plus Kotlin runtime logic
• NOT compatible with the Zombies Ignore LOS and the Zombies Apocalyptic AI mods. Both of which this mod was written to replace.

How Configuration Works

• All settings are changed in-game through commands.
• Command roots: czai and configurablezombieai
• Permission level: operator level 2
• Settings are saved in world data, so they persist across restarts.
• When settings change, loaded zombies are refreshed immediately.

Command Reference

Examples below use the short root command, but every command also works with configurablezombieai instead of czai.

Core Commands

Command	Description
czai enable	Enables all mod behavior.
czai disable	Disables all mod behavior and restores vanilla follow range for loaded zombies.
czai status	Prints the current live configuration.
czai ignore_LOS <true	false>
czai despawn_prevention <true	false>
czai visibility_range <blocks>	Sets the zombie follow range / detection distance.

Acquisition Tuning

These settings affect how a zombie picks an initial target after vanilla has already decided that a target goal may run.

Command	Description
czai acquisition distance_variability_from_closest_target <blocks>	Expands the initial candidate pool beyond the closest target by the given distance.
czai acquisition chance_to_auto-select_closest_target <percent>	Chance to guarantee the closest available target is chosen. At 100, the closest target always wins. At 0, any candidate in the acquisition pool may be chosen.

Switching Tuning

Switching is off by default. When enabled, zombies periodically re-roll their target inside the same target family as the current one.

Command	Description
czai switching enabled <true	false>
czai switching interval <ticks>	How often each zombie evaluates target switching.
czai switching search_radius <blocks>	Radius used to collect alternative targets for switching.
czai switching proximity_bias <value>	Positive values favor nearer candidates; negative values favor farther ones.
czai switching current_target_bias <value>	Positive values make the zombie more likely to stay on its current target.
czai switching closer_than_current_target_bias <value>	Positive values reward candidates that are closer than the current target.

Utility Commands

Note: You need level 2 permissions (OP) to use these commands.

Command	Description
czai kill all	Kills all loaded zombies across every loaded dimension.
czai kill radius <blocks>	Kills zombies within a radius of the executing player.

Default Values

Setting	Default
Mod enabled	true
Ignore line of sight	false
Prevent despawn	false
Visibility range	35.0 blocks
Acquisition distance variability	0.0 blocks
Chance to auto-select closest target	100.0%
Switching enabled	false
Switching interval	40 ticks
Switching search radius	16.0 blocks
Switching proximity bias	0.0
Switching current target bias	1.0
Switching closer-than-current-target bias	1.5

Targeting Notes

• Acquisition still respects vanilla target categories such as players, villagers, iron golems, and baby turtles on land.
• Switching does not jump between target families. If a zombie is currently chasing a villager, it will only compare that villager against other villager candidates during a switching pass.
• Line-of-sight bypass still respects attack validity checks and the configured visibility range.