CobbleChunkManager

A server-side Fabric mod for Cobblemon 1.7+ on Minecraft 1.21.1 that manages per-chunk Pokemon entity density to reduce server lag.

What it does

Spawn Prevention — Hooks into Cobblemon's spawn event and cancels Pokemon spawns in chunks that are already at the entity budget (default 16 per chunk). This is the main performance feature — it stops entities from being created in the first place, reducing total entity count on the server.

Heatmap System — Tracks every loaded chunk's activity: Pokemon count, player presence, active battles. Each chunk is classified as HOT (active area with players/battles), WARM (moderate activity), or COLD (empty/idle). Scans 50 chunks every 5 seconds.

Budget Enforcement — Every 10 seconds, finds chunks over the entity budget and handles the excess wild Pokemon using the configured strategy:

• MIGRATE — teleport excess to nearby chunks with free space
• DESPAWN — remove excess wild Pokemon
• MIGRATE_THEN_DESPAWN (default) — try to migrate first, despawn whatever can't be relocated

Only wild Pokemon that aren't in battle or busy are affected. Owned Pokemon are never touched.

AI Throttling — Disables vanilla AI (pathfinding, movement goals) for Pokemon in COLD chunks. Only triggers when a chunk's heat level changes, so the per-tick cost is near zero.

Commands

• /ccm heatmap [radius] — visual grid of nearby chunk heat levels and entity counts
• /ccm status — detailed info for the current chunk
• /ccm budget — server-wide budget overview, lists over-budget chunks
• /ccm migrate — manually trigger overflow handling in the current chunk
• /ccm reload — hot-reload the config file

Config

All values are configurable via config/cobble_chunk_manager.json — thresholds, budget limits, scan intervals, overflow strategy, migration behavior.