Chunksmith is a Minecraft chunk pre-generator that paces generation to keep your server healthy. It builds large areas ahead of time without saturating your disk or freezing the server. A maintained fork of Chunky by pop4959, licensed under GPL-3.0, maintained by Kishku7.

On slower hardware, a heavy pre-gen can saturate disk I/O, leaving the server unresponsive to pause or stop commands, and on an empty server it may even send it to sleep mid-run. Chunksmith focuses on generating safely under real-world conditions. It uses an adaptive I/O throttle that steers generation concurrency by live server tick-health on Fabric, NeoForge, and Paper. It backs off when the server starts to fall behind and ramps back up as it recovers, with a per-chunk latency backstop guarding against disk stalls on every platform. You can run it 24/7, even with players online.

New in version 1.1.0 is a worldgen overreach diagnostic. When a worldgen feature or structure tries to setBlock outside its chunk, which vanilla refuses and normally spams 100-200 near-identical log lines per occurrence, Chunksmith now collapses the whole burst into a single readable report. It names the offending feature, the affected chunks, the Y range, and the block count, so you can identify and report the culprit mod instead of drowning in log noise. Full structured detail is available on Fabric and NeoForge (one version-portable binary across the entire 26.1-26.2 range) and best-effort on Paper, Spigot, and Folia.

Key features include:

Adaptive I/O throttle based on server tick health
Per-chunk latency backstop to prevent disk stalls
Worldgen overreach diagnostic (1.1.0) that collapses log spam into one report
Runs safely 24/7 even with players online
Maintained fork with active updates

Requirements: Chunksmith works on Fabric, NeoForge, Paper, Spigot, and Folia servers. It requires Java 17 or later. The worldgen overreach diagnostic provides full structured detail on Fabric and NeoForge (26.1-26.2) and best-effort on Paper/Spigot/Folia. Note that it is a fork of Chunky and retains the same basic commands and configuration; existing Chunky users can migrate their settings. The adaptive throttle relies on tick health monitoring; on platforms without that API (e.g., vanilla servers) it falls back to a simpler fixed concurrency mode.

Chunksmith - Adaptive Chunk Pre-generator