Borrowing it
Nothing to install: this file belongs to chapmanjw/minecraft-java-fabric-claude-plugin. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/chapmanjw/minecraft-java-fabric-claude-plugin/main/CLAUDE.mdgit clone --depth 1 https://github.com/chapmanjw/minecraft-java-fabric-claude-pluginWrote 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.
[](https://agentmods.dev/instructions/chapmanjw/minecraft-java-fabric-claude-plugin/claude-md)<a href="https://agentmods.dev/instructions/chapmanjw/minecraft-java-fabric-claude-plugin/claude-md"><img src="https://agentmods.dev/badge/instructions/chapmanjw/minecraft-java-fabric-claude-plugin/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.
<a href="https://agentmods.dev/instructions/chapmanjw/minecraft-java-fabric-claude-plugin/claude-md"><img src="https://agentmods.dev/badge/instructions/chapmanjw/minecraft-java-fabric-claude-plugin/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.02351 | $0.02351 |
| Opus 5.5 | $0.00940 | $0.00940 |
| Sonnet 5.5 | $0.00470 | $0.00470 |
| Haiku 4.5 | $0.00235 | $0.00235 |
Grade A, and why
minecraft-java-fabric-claude-plugin 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Commands
node scripts/validate-plugin.mjs # validate manifests, frontmatter, and skill/folder name alignment (Node 20+)
python -m pip install -r tools/requirements.txt # one-time: deps for the voxel + terrain toolkits (numpy, Pillow, scipy; optional opensimplex)
python tools/examples/example_bean.py # smoke-test the voxel toolkit (renders 3 PNGs + a fills JSON)
No build step for the markdown content — skills and agents are plain markdown
and take effect in the next Claude Code session after the plugin is reloaded.
The tools/ directory adds a small Python helper layer (the voxel and
terrain toolkits) that the builder skills run locally; the voxel toolkit is
numpy + Pillow, the terrain toolkit adds scipy (+ optional opensimplex), and
the builder harness is stdlib-only. They are referenced from skills via
${CLAUDE_PLUGIN_ROOT}/tools/…. These helpers
run in Claude Code (CLI or desktop app), where the agent has local Bash and
can read the PNGs they produce.
Architecture
This is the Claude-facing piece of a two-repository system. The MCP server is embedded in the Fabric mod and runs inside Minecraft — there is no separate server process and no behavior pack.
The mod has two entrypoints / two MCP endpoints from one jar:
Claude (Code / Desktop)
│ MCP over Streamable HTTP │ MCP over Streamable HTTP
│ minecraft-java (127.0.0.1:8765/mcp) │ minecraft-java-client (127.0.0.1:8766/mcp)
▼ ▼
McpServerMod (main entrypoint) McpClientMod (client entrypoint)
│ server API, server main thread │ client API, client/render thread
│ WORLD tools (level_/block_/entity_…) │ INSPECTION tools (view_capture, sense_*, client_status)
▼ ▼
the Minecraft world ◄──── same world, the client joins as a player ────►
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.
- 1mo ago First seen · 125 lines · 2,351 tokens per session scan A 220937047efe
minecraft-java-fabric-claude-plugin CLAUDE.md is an instructions file published in the GitHub repository chapmanjw/minecraft-java-fabric-claude-plugin (8 stars, last pushed 1mo ago), licensed MIT. It adds 2,351 tokens to every session, about $0.0094 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.
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