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Cairn

Introduction

Cairn is a description language for Minecraft builds. You declare intent — walls, roofs, windows, symmetry, themes, redstone logic — and the compiler resolves the voxels: blockstates, orientations, coordinate math, signal routing, and per-edition/per-version block IDs.

A cairn is a deliberately stacked pile of stones that marks a place. A Minecraft build is exactly that — intentionally placed blocks. The name is the thesis.

What it solves

Section titled “What it solves”

Minecraft’s NBT/SNBT is inefficient for AI to read and write (binary, one-record-per-block) and misaligned with how humans and AI reason about architecture (walls, roofs, symmetry). Cairn sits between an AI’s general architectural knowledge and Minecraft’s voxel world.

The portable artifact is always the Cairn source; emitted NBT and schematics are per-target build outputs, the equivalent of a compiled binary. Targeting a new Minecraft version means recompiling the source, not transcoding the NBT.

What it deliberately does not do

Section titled “What it deliberately does not do”
  • Full round-trip fidelity with NBT. Generation-first is lossy by design. Imported schematics are kept as a faithful low-level transliteration that an LLM can lift into idiomatic Cairn, with a voxel-diff loop driving convergence.
  • General sequential synthesis of arbitrary state machines or CPUs in redstone. v1 ships combinational gates plus a curated macro library; everything else drops to physical placement or a raw escape hatch.
  • Pre-1.13 numeric-ID .schematic import. v1 does not support flattening.

See Purpose and Scope for the normative wording.

Section titled “Where to read next”

Status

Section titled “Status”

Cairn is at the design stage, draft 2026.06. The language is being designed in the open and the reference compiler is a skeleton — the most useful contributions right now are design critique, concrete proposals, and worked examples. See CONTRIBUTING.md.