Lachesis MCP server

Lachesis is a helper that reads your code and builds a map of it. Once the map is built, you can ask questions like who calls this function, or can outside input reach a database call with no login check. It works on C, Python, and TypeScript/JavaScript, and it is handy for anyone who has to understand code they did not write.

What this MCP server does

You point Lachesis at a folder of code, and it reads the files the way a compiler does, not by searching for words. It builds a map of functions, calls, and how values move from place to place. Then your AI can ask that map questions through this server. You get back answers like a list of callers, a path showing how a value travels, or a warning that outside input can reach something sensitive with no check in the way.

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What you can do with it

• Find who calls a function and what it calls
• Trace where a value comes from and where it goes
• Check whether outside input can reach a dangerous spot
• Show the real source code of a function
• List what a file or folder contains
• Find where a name appears in the code
• See what a pointer points at in C code

Try asking your AI

• “Who calls the handleWebhook function in my project?”
• “Can user input from the web route reach the database call in webhook.ts?”
• “Show me the source of the findById function”
• “What functions are called from the main entry point?”

What it gives back to you

You get answers in the chat, like a list of function names, a path showing how data moves from one place to another, or a short summary of spots worth looking at. Each answer comes with how sure Lachesis is, so you know when it is guessing. For some questions it shows the actual source code of a function. It does not change your code; it only reads it and reports back.

Before you start

Who it's for

Developers, security reviewers, and anyone who needs to understand a codebase they did not write.