What is just-mcp CLAUDE.md?

A repository guide for coding agents working on a Rust server that connects Justfiles—files containing command recipes—to the MCP standard for connecting tools to AI assistants. It documents the project structure, available tools, and completed work.

Use it when an agent needs to understand this repository, look up Rust crate or other library documentation, plan small or large changes, or check which major project tasks are complete.

It gives an agent the project context and working rules in one place, reducing time spent guessing how the codebase and its documentation tools are organized.

How PromptExecution/just-mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to PromptExecution/just-mcp. 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/PromptExecution/just-mcp/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/PromptExecution/just-mcp

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

Your own site

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

Per session 1,008 This file is loaded in full into every session.

When invoked 1,008 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	$0.01008	$0.01008
Opus 5.5	$0.00403	$0.00403
Sonnet 5.5	$0.00202	$0.00202
Haiku 4.5	$0.00101	$0.00101

Measured 2mo ago against content hash 3deaf2d62073, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

just-mcp 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 · 94 lines

How it starts

The opening of the file, as written. The whole thing — 94 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.

🤓 MCP-Tools

use rust-crate-doc tool to query specific info on crates, traits, etc.
use context7 for information on all other documentation
use sequential thinking for small step by step planning
use taskmaster-ai for big picture phases

Project Overview

This is just-mcp, a production-ready MCP (Model Context Protocol) server for Justfile integration. Current Status: 67% complete (8/12 core tasks done) with full rmcp 0.3.0 integration already implemented and tested.

✅ Major Milestones Completed

✅ Complete MCP Server - Full rmcp 0.3.0 integration with MCP 2024-11-05 protocol
✅ Recipe Discovery & Execution - Parse, list, and execute Justfile recipes with parameters
✅ Comprehensive Testing - 33 passing tests including integration and unit test suites
✅ Environment Management - .env file support and variable expansion
✅ Production Ready - Structured error handling, async support, JSON-RPC compliance

Architecture

The project is designed to be a Rust-based MCP server that provides:

Justfile parsing and introspection
Recipe execution with structured output
LSP-style completion and validation
JSON-RPC interface for LLM integration

Based on TODO.pm, the planned architecture includes:

just-mcp binary crate (CLI interface)
just-mcp-lib library crate (core functionality)
12-phase development roadmap from basic parsing to full MCP protocol compliance

Development Environment

This project follows the b00t development methodology as documented in AGENTS.md:

Tech Stack

Rust: Stable 1.82+ with cargo CLI
Error Handling: Use snafu crate for structured error management
Development Tools: just command runner, uv/uvx for Python tooling

Development Practices

TDD: Add tests first, then implement code
Git Workflow: Never work directly on main/dev branch - always create feature branches
6C Turbo-Agile: Use contextual comments → commit code → cleanup/cull pattern for refactoring
Branch Naming: Use feature/, fix/, or chore/ prefixes with GitHub issue numbers

Read the full file on GitHub · 94 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 · 94 lines · 1,008 tokens per session scan A 3deaf2d62073

Subscribe to this mod's changes

just-mcp CLAUDE.md is an instructions file published in the GitHub repository PromptExecution/just-mcp (60 stars, last pushed 3mo ago), licensed MIT. It adds 1,008 tokens to every session, about $0.0040 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.

just-mcp CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
just-mcp CLAUDE.mdPromptExecution/just-mcp	Instructions file	60	3mo ago	MIT	A	1,008	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

just-mcp: Instructions file for Claude Code