Building a Local Digital Brain for Claude

Building a Local Digital Brain for Claude Building a Local Digital Brain for Claude A fully local, persistent knowledge layer over a folder of PDFs — embeddings, a knowledge graph, and an MCP server Claude can call into. No API keys. Nothing leaves your laptop. Claude is excellent at general reasoning, but out of the box it doesn't know your team's documentation, your design notes, or that 400-page reference PDF you've been meaning to read. I wanted a way to point Claude at a folder of my own materials and have it actually use them — to ground answers, write code in our conventions, and cite specific pages — without sending anything to the cloud. This post walks through what I built: a fully local, persistent "digital brain" over a folder of PDFs, exposed to Claude Desktop, Claude Code, and Cowork via a single MCP server. Embeddings come from Ollama, vectors live in ChromaDB, and a knowledge graph of entities and relationships lives in NetworkX —...