How I Built an MCP Server to Let Claude Organize My OneNote Notebook (And Beat a 501 Error)

TL;DR: I built an open-source MCP server for Microsoft OneNote in Python. It connects Claude (or any MCP-compatible AI) directly to your OneNote notebooks. The tricky part: Microsoft's copyToSection API returns a 501 on personal accounts. Here's the workaround — and the full story of why I built it. The Problem: A Notebook Full of Chaos Three years of notes. 200+ pages. Dozens of sections with names that made sense at the time. Zero structure. I wanted to reorganize my OneNote notebook, but doing it manually was out of the question. So I asked: what if I could give Claude access to OneNote directly, and let it do the work? That question led me to build onenote-mcp-server . What Is MCP? Model Context Protocol (MCP) is an open standard from Anthropic that lets AI assistants connect to external tools and services through a structured, typed interface. You build an MCP server that exposes "tools" — essentially callable functions — and any MCP client (Claude Desktop, Cursor, Zed, Continue.d