What is mcp-javadc CLAUDE.md?

Development instructions for an MCP server that decompiles Java code. MCP is a standard way for AI tools to call external programs.

Installing dependencies, running or testing the server, creating Java test samples, and checking its tools with MCP Inspector.

It gives an AI coding assistant the project layout, commands, and testing steps needed to work on the server correctly.

How idachev/mcp-javadc configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to idachev/mcp-javadc. 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/idachev/mcp-javadc/master/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/idachev/mcp-javadc

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/idachev/mcp-javadc/claude-md/github.svg)](https://agentmods.dev/instructions/idachev/mcp-javadc/claude-md)

Your own site

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

Per session 411 This file is loaded in full into every session.

When invoked 411 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	$0.00411	$0.00411
Opus 5.5	$0.00164	$0.00164
Sonnet 5.5	$0.00082	$0.00082
Haiku 4.5	$0.00041	$0.00041

Measured 2mo ago against content hash 8f72d165727a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-javadc 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 · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP Java Decompiler Server - Claude Development Guide

This file contains development-focused instructions and context for Claude when working on this project.

Project Structure

index.js: Main server file that contains all the logic

Development Commands

# Install dependencies
npm install

# Run in development mode
npm run dev

# Run the server
npm start

# Create test fixtures (sample Java class for testing)
npm run test:setup

# Run tests
npm test

# Use MCP Inspector for interactive testing
npx @modelcontextprotocol/inspector node ./index.js

Implementation Details

The server is built on the MCP SDK with:

Server class for core functionality
Tool registration with parameter schemas
Standard response formatting
StdioServerTransport for I/O communication

Key Code Sections

Server Initialization: Setup with name and version
Tool Registration: Handlers for the decompiler functions
Request Handling: Functions for the core MCP protocol methods
Decompiler Service: Implementation of the decompiler functionality
Transport Setup: Configuration for stdio transport

Protocol Handler Registration

The server registers these protocol handlers:

ListToolsRequestSchema: Handles mcp.tool.list to return available tools with parameter schemas
CallToolRequestSchema: Handles mcp.tool.execute to execute tools with validation

Development Troubleshooting

Common development issues:

If adding new tool parameters, update both the schema and the handler function
If changing decompiler options, test with various Java versions
When modifying JAR handling, ensure proper cleanup of temporary files
Proper error handling is essential for MCP protocol compatibility
Test with the MCP Inspector to verify tool registration and execution
If you encounter "Method not found" errors, check protocol handler registration
Version numbers must be updated in both package.json and the SERVER_VERSION constant

Read the full file on GitHub · 66 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 · 66 lines · 411 tokens per session scan A 8f72d165727a

Subscribe to this mod's changes

mcp-javadc CLAUDE.md is an instructions file published in the GitHub repository idachev/mcp-javadc (20 stars, last pushed 1y ago), licensed ISC. It adds 411 tokens to every session, about $0.0016 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 2026-08-30.

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mcp-javadc: Instructions file for Claude Code