yoyo: Local MCP Server for Grounded Codebase Reads and Guarded Writes with Claude Code
What yoyo Does
yoyo is an open-source local MCP server designed for working on real codebases with coding agents, including Claude Code. The tool was built partly with Claude/Claude Code and is designed to be useful from Claude Code itself.
Core Features
- Grounded repo reads: Provides agents with capabilities like
inspect,judge_change, andimpact - Guarded writes: Prevents broken edits from silently landing in the codebase
- Structured feedback: Returns machine-readable
guard_failureoutput when a write fails - Retry mechanism: Adds
retry_planso the next repair step is narrower and more targeted - Runtime guards: Supports runtime guards for interpreted languages, allowing files to be rolled back if they parse but still fail at runtime
Language Support
Currently supports 16 languages: Rust, Go, Python, TypeScript, JavaScript, C, C++, C#, Clojure, Java, Kotlin, PHP, Ruby, Swift, Bash, and Zig.
Practical Example
A Python edit might pass a syntax check but still fail because of a missing import or undefined name. yoyo can catch that in the runtime guard, restore the original file, and return structured feedback for the next fix attempt.
Recent Updates
Recent work added initial Clojure support and least-privilege runtime config bootstrap.
Availability
The tool is free to try and open source at https://github.com/avirajkhare00/yoyo.
📖 Read the full source: r/ClaudeAI
👀 See Also
cldctrl: Terminal Dashboard for Managing Claude Code Sessions
cldctrl is an npm package that provides a terminal dashboard for launching and managing Claude Code sessions across projects. It reads existing ~/.claude data, auto-discovers projects, and shows token usage with rate limit bars.
Docent: An AI Assistant for Paper Analysis Built with Claude Code
A developer created Docent, an AI assistant that reads uploaded papers, presents them, answers questions, and assesses understanding using Claude Code. The project is available on GitHub under MIT License with a demo on Vercel.
ExposureGuard MCP Server Adds Domain Security Scanning to Claude Desktop
A developer built an MCP server for domain security scanning using Claude Code, exposing four tools that check SPF, DMARC, SSL, security headers, DNSSEC, open ports, MX, and HTTPS. The server is available via pip install exposureguard-mcp with a free tier of 100 API calls per day.
Clooks: A Persistent Hook Runtime for Claude Code
Clooks is a persistent HTTP daemon that handles Claude Code hook dispatch without process spawning, reducing latency from ~34.6ms to ~0.31ms per invocation. It includes automatic migration, LLM handlers with prompt templates, dependency resolution, and plugin packaging.