What is mc-dev CLAUDE.md?

A Minecraft development reference for Forge, NeoForge, Fabric, Paper, and Spigot, organized around API changes between Minecraft versions.

Use it to check version-specific APIs, find official documentation, and make development decisions for Minecraft mods or server software.

Minecraft APIs can change in ways that break code, especially across versions 1.20.5 and 1.21.4.

How sikadi233-hub/mc-dev configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to sikadi233-hub/mc-dev. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/sikadi233-hub/mc-dev/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/sikadi233-hub/mc-dev

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/sikadi233-hub/mc-dev/claude-md/github.svg)](https://agentmods.dev/instructions/sikadi233-hub/mc-dev/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/sikadi233-hub/mc-dev/claude-md"><img src="https://agentmods.dev/badge/instructions/sikadi233-hub/mc-dev/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/sikadi233-hub/mc-dev/claude-md"><img src="https://agentmods.dev/badge/instructions/sikadi233-hub/mc-dev/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 2,254 This file is loaded in full into every session.

When invoked 2,254 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.02254	$0.02254
Opus 5.5	$0.00902	$0.00902
Sonnet 5.5	$0.00451	$0.00451
Haiku 4.5	$0.00225	$0.00225

Measured 2mo ago against content hash 59bfc59ae481, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mc-dev CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md - Minecraft 开发知识库

本文件是 mc-dev 工具链的共享知识库，mc-expert / mc-framework / mc-content / mc-review 均依赖它的版本边界与 API 速查。 最后校验：2026-07（Maven 坐标 / API 仍会过时，生成前请 WebFetch 确认最新版本）

1. 官方文档索引

平台	官方文档
Forge	https://docs.minecraftforge.net/en/latest/
NeoForge	https://neoforged.net/
Fabric	https://docs.fabricmc.net/develop/ （版本化：/1.21.4/develop/）
Paper	https://docs.papermc.io/
Spigot	https://www.spigotmc.org/wiki/spigot/
社区 Wiki	https://moddedmc.wiki/ , https://wiki.fabricmc.net/start

2. 关键版本边界（核心）

Minecraft 1.20.5 和 1.21.4 是两个 API 断裂点。所有代码决策都从版本分组出发：

Group A: <= 1.20.4 - 旧 NBT
Group B: 1.20.5 - 1.21.3 - Data Components，旧 custom_model_data（单个 int）
Group C: >= 1.21.4 - 新 custom_model_data（list 结构）、新 item model 系统、服务端 pick block

断裂点 1：1.20.5 - Data Components 替代 NBT

旧 API (`<= 1.20.4`)	新 API (`>= 1.20.5`)
`stack.getTag()` / `stack.getOrCreateTag()`	`stack.get(DataComponentType)` / `stack.set(type, value)`
`stack.getTag().putInt("key", val)`	`stack.set(MyMod.MY_COMPONENT.get(), val)`
NBT 手动序列化	`DataComponentType` + Codec 自动序列化
`Item.Properties#stacksTo(n)` / `fireResistant()`	迁移到 Data Components（如 `minecraft:max_stack_size`）
附魔通过 NBT List	附魔通过 `minecraft:enchantments` Data Component
物品伤害值 NBT	`minecraft:damage` Data Component

新的注册模式 (>= 1.20.5)：

// Fabric / Vanilla
DataComponentType<Integer> MY_COMP = Registry.register(
    BuiltInRegistries.DATA_COMPONENT_TYPE,
    ResourceLocation.fromNamespaceAndPath("modid", "my_comp"),
    DataComponentType.<Integer>builder().persistent(Codec.INT).build()
);

// Forge / NeoForge: 同样使用 vanilla 的 DataComponentType 系统
public static final DeferredRegister<DataComponentType<?>> DATA_COMPONENTS =
    DeferredRegister.create(BuiltInRegistries.DATA_COMPONENT_TYPE, "modid");

断裂点 2：1.21.4 - 进一步 API 重构

变更项	说明
custom_model_data 重构	从单个 int -> `{strings:[], floats:[], flags:[], colors:[]}` 结构
Item Model Definition	新系统替代旧 model JSON；ItemColors / tint 系统被移除
Pick Block 移到服务端	`ClientPickBlockCallback` -> `PlayerPickItemEvents#BLOCK` (Fabric)
BuiltinItemRenderer	被移除（Fabric API fabric-rendering-v0 删除）
`CustomIngredient#getMatchingStacks`	返回 Stream 替代 List (Fabric)
DataComponentIngredient	新类型 `neoforge:ingredient_type` 替代旧 `"type": "neoforge:components"` (NeoForge)
Client Data Generation	Loom 新增 `configureDataGeneration { client = true }` (Fabric)

Read the full file on GitHub · 173 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 173 lines · 2,254 tokens per session scan A 59bfc59ae481

Subscribe to this mod's changes

mc-dev CLAUDE.md is an instructions file published in the GitHub repository sikadi233-hub/mc-dev (2 stars, last pushed 3mo ago), licensed MIT. It adds 2,254 tokens to every session, about $0.0090 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Game development

mc-dev CLAUDE.md next to 6 instructions from other repositories
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mc-dev: Instructions file for Claude Code