minecraft-dev

A command-line lookup tool for Minecraft, the block-building game, and its modding ecosystem. It can inspect game and mod source, loader details, mappings, registries, versions, and documentation.

In plain words
What is it for?
Use it to find classes and symbols, inspect mod or loader code, look up registries and mappings, compare versions, and check Fabric, Forge, Quilt, or NeoForge details.
Why use it?
It avoids searching through large game or mod files by hand. It also helps match code names and APIs to a specific Minecraft version and mapping system.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/mcdxai/minecraft-dev-mcp/minecraft-dev
Any agent
npx skills add MCDxAI/minecraft-dev-mcp --skill minecraft-dev
Clone the repo
git clone --depth 1 https://github.com/MCDxAI/minecraft-dev-mcp

Made for: Claude Code, Codex.

Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,235 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00068 $0.01235
Opus 5 $0.00034 $0.00617
Sonnet 5 $0.00014 $0.00247
Haiku 4.5 $0.00007 $0.00123

Measured 2d ago against content hash 7147fa527a9a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

minecraft-dev 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 2d 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.

skills/minecraft-dev/SKILL.md · 117 lines

How it starts

The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Minecraft Dev CLI Lookup

Use minecraft-dev-cli to inspect Minecraft code, mod and loader JARs, mappings, registries, versions, and docs.

Version format note

Use the actual Minecraft version the user is working with. Modern releases use the newer 26.1.x naming style, for example 26.1.2.

  • 1.14 through 1.21.11 support both yarn and mojmap.
  • 26.1+ uses mojmap only.
  • Yarn mappings stop at 1.21.11.

Workflow

  1. Identify whether the user needs Minecraft source, mod source, mod loader metadata, mappings, registries, docs, validation, or version diffing.
  2. Pick the narrowest tool that answers the request.
  3. Run minecraft-dev-cli <tool> --key value or minecraft-dev-cli <tool> --key=value.
  4. Parse the JSON response and return only the useful result.
  5. If the request is vague, ask for the class name, file path, symbol, JAR path, or Minecraft version.

Tool List

Core Minecraft source

  • get_minecraft_source — get decompiled source for one Minecraft class.
  • decompile_minecraft_version — decompile an entire Minecraft version into cache.
  • list_minecraft_versions — list available and cached Minecraft versions.
  • get_registry_data — extract block, item, entity, and other registry data.
  • search_minecraft_code — regex search through decompiled Minecraft source.
  • index_minecraft_version — build a fast full-text index for Minecraft source.
  • search_indexed — run fast indexed searches against Minecraft source.

Mappings and comparison

  • find_mapping — translate class, method, and field names between mapping systems.
  • remap_mod_jar — remap a Fabric mod JAR to readable names.
  • compare_versions — compare two Minecraft versions at a high level.
  • compare_versions_detailed — compare versions with AST-level API detail.

Validation and documentation

  • analyze_mixin — validate Mixin targets and injections against Minecraft source.
  • validate_access_widener — validate access widener targets against Minecraft source.
  • validate_access_transformer — validate a Forge/NeoForge access transformer (.cfg) against Minecraft source (mojmap-only); flags bad targets/signatures, record canonical-constructor crashes, inner-class accessibility, and conflicting modifiers.
  • get_documentation — fetch documentation hints for a Minecraft class or concept.
  • search_documentation — search known Minecraft and Fabric docs.

Read the full file on GitHub · 117 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

  1. 2d ago First seen · 117 lines · 68 tokens per session scan A 7147fa527a9a

Subscribe to this mod's changes

minecraft-dev is a skill published in the GitHub repository MCDxAI/minecraft-dev-mcp (35 stars, last pushed 26d ago), licensed MIT. It adds 68 tokens to every session and 1,235 once invoked, about $0.0003 per session on Opus 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 2026-08-30.

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