Nelson MCP — LibreOffice MCP server

Nelson MCP

A LibreOffice extension that turns your documents into an MCP server. External AI clients connect over HTTP and get full access to document tools — reading, editing, navigating, formatting, and more.

Works with any MCP-compatible client: Claude Code, OpenCode, Goose, ollmcp, etc.

How it works

Nelson MCP runs an HTTP server inside LibreOffice and speaks the Model Context Protocol. AI agents connect to it and use tools to interact with your open document — no copy-paste, no file export.

┌─────────────────┐     HTTP/MCP     ┌────────────────┐
│  AI Client      │ ───────────────► │  LibreOffice   │
│  (Claude Code,  │    tools/call    │  + Nelson MCP  │
│  OpenCode…)     │ ◄─────────────── │                │
└─────────────────┘   tool results   └────────────────┘

What it looks like

An agent writes a quarterly report into an empty Writer document, one tool call at a time:

The finished report: the content as Markdown, heading colours with styleset, a shaded table, a Page {page} of {pages} footer, and a comment on the hiring line. The Nelson MCP** sidebar logs every call. Select a call to see its caller, status, duration and parameters.

Everything is set in Tools > Options > Nelson. For example, the HTTP page sets the port, the bind address and the access token:

Features

• 145 document tools — read content, edit text, manage styles, insert images, handle tables, charts, conditional formatting, hyperlinks, track changes, page headers/footers, navigate headings, search, and more. The list is filtered by the active document type, so a client sees only what applies (97 with a Writer document, 50 with Calc)
• Self-configuring agents — with the config API on, an agent reads and changes Nelson's settings itself (read limits, exchange format, the name on its changes), while the settings that protect you stay reserved to Options. See Let the agent configure Nelson
• Custom MCP endpoints — expose only the tools your agent needs. Built-in presets (minimal, writer-edit, writer-read, calc, gallery) or create your own filtered endpoints
• Writer, Calc, Draw, Impress — tools adapt to the active document type
• Calc =PROMPT() — call an LLM directly from a spreadsheet cell
• Built-in launchers — launch Claude Code, Gemini CLI, or OpenCode directly from LibreOffice with one click. Nelson handles MCP config, prompt injection, and working directory setup automatically
• AI image generation — generate and edit images from text prompts using Stable Diffusion (A1111/Forge), OpenAI, or AI Horde. One-click detect/install/launch for Automatic1111
• Beginner-friendly setup — all tools come with install buttons, auto-detection of existing installations, and guided configuration. No manual config files to edit
• Tunnels — expose the MCP server externally via ngrok, Cloudflare, bore, or Tailscale, behind an access token
• SSL — optional HTTPS with auto-generated certificates
• Modular — each feature is a self-contained module with its own config, services, and tools

Install

Shortened. The full README is on GitHub.