Nelson MCP — LibreOffice MCP server: what it does
A LibreOffice extension that runs an MCP HTTP server inside the office suite. Agents read and edit your open Writer, Calc, Draw and Impress files.
Open on GitHubWhat Nelson MCP — LibreOffice does
Nelson MCP is a LibreOffice extension that turns the suite into an MCP server. An HTTP service starts inside LibreOffice and speaks the Model Context Protocol, so an external AI client connects at http://localhost:8766/mcp. There is no copying text into a chat window and no exporting a file first — the agent works against the document you already have open.
The tool set is large, 145 across the board, but a client only sees what fits the active document type: 97 with Writer, 50 with Calc. Reading content, editing text, styles, tables, charts, headers and footers, search, track changes. Calc also gets =PROMPT(), which calls an LLM from a cell. Settings live under **Tools > Options > Nelson** — port, bind address, access token.
By default the server binds to localhost, which is all a client on your own machine needs. Anyone who can reach Nelson, though, can read and edit every open document and open any file your account can read. That is why it will not listen beyond localhost or start a tunnel until a token is set. The token goes in **Options > Nelson MCP > HTTP > Access Token** and takes effect without a restart.
What it helps with
- read an open Writer document and summarize its content
- build a report step by step in an empty document
- fix styles and formatting in the file that is already open
- call an LLM from a Calc cell with
=PROMPT() - run an MCP server over an office document without exporting it
Example prompts for the agent
- Read the open Writer document and list its headings
- Add a heading, a table of quarterly numbers and a footer to the empty report
- Call an LLM from a Calc cell with
=PROMPT()and put the answer in the next cell
How to install Nelson MCP — LibreOffice
Install
The MCP registry has no launch command for it: see the repository README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Nelson MCP — LibreOffice
How do I install Nelson MCP in LibreOffice?
Download the latest .oxt from the releases page, then in LibreOffice open **Tools > Extension Manager > Add** and pick the file. Restart LibreOffice and the server starts on its own at http://localhost:8766/mcp.
What does Nelson MCP do?
It runs an MCP server inside LibreOffice, letting an AI client read and edit open Writer, Calc, Draw and Impress documents through tools instead of manual copy-paste.
What do I need to connect an agent to Nelson MCP?
Point your MCP client at the HTTP server http://localhost:8766/mcp. If the server is reachable over a network or through a tunnel, set an access token in Nelson's options first.
