ONLYOFFICE Presentation MCP Bridge

Let an AI assistant work directly inside the presentation you have open in ONLYOFFICE.

Most presentation agents generate a new .pptx file every time they make a change. That workflow is slow, creates duplicate files, and can overwrite work you have already refined by hand. ONLYOFFICE Presentation MCP Bridge takes a different approach: it connects an MCP-compatible assistant to the presentation currently open in ONLYOFFICE Desktop Editors.

The assistant can inspect the deck, understand its slide structure, and make targeted changes to native presentation objects. You keep working in the same editor and remain in control of every mutation.

The bridge runs entirely on your computer. It does not upload your presentation to a separate document service, and it never gives the assistant an arbitrary JavaScript execution endpoint.

Project status: early preview. Live inspection and targeted editing work, but automatic saving and general undo are still limited by the ONLYOFFICE 9 plugin API. Use a disposable copy for your first tests.

Why use it?

• Work on the open presentation instead of generating another copy.

• Preserve manual edits by changing only the requested slide objects.

• Keep slides editable with native text boxes and presentation elements.

• Inspect before changing with slide and object metadata exposed through MCP.

• Stay local with a loopback-only, authenticated connection.

• Keep control because every mutating tool requires explicit confirmation.

Related MCP server: PowerPoint MCP Server

What can it do today?

• Inspect the open presentation and its slide structure.

• Inspect individual drawings with their geometry and limited semantic data.

• Add editable text boxes.

• Replace text inside an existing shape.

• Delete a slide.

• Delete an inspected drawing with an exact geometry safety check.

• Roll back the latest object added by the bridge.

It is designed for MCP clients such as OpenCode, but the server follows the Model Context Protocol and can be connected to other compatible clients.

Security model

• The WebSocket listens only on 127.0.0.1:2021.

• A random 256-bit token authenticates the ONLYOFFICE plugin.

• The token is generated locally and is never part of the repository.

• The plugin exposes a fixed allowlist. It cannot execute arbitrary JavaScript.

• Mutating MCP tools require confirm: true.

• Commands are serialized and have a 10-second timeout.

• Drawing deletion additionally checks the object's exact inspected geometry.

The MCP client and every process running as the same operating-system user are inside the trust boundary. See SECURITY.md for limitations.

Requirements

• Linux desktop

• Node.js 20 or newer

• ONLYOFFICE Desktop Editors 9 (tested with 9.0.3)

• An MCP client such as OpenCode

Installation

npm ci
npm test
npm run check
npm run install:plugin

Register the server in OpenCode:

opencode mcp add onlyoffice-presentation --global -- node "$PWD/server.mjs"

Restart ONLYOFFICE Desktop Editors after installing the plugin, then open a presentation. The MCP server itself is started by the MCP client.

Token rotation

If the token is exposed, rotate it and restart both the MCP server and ONLYOFFICE Desktop Editors:

npm run rotate-token

Never commit bridge-token or plugin/token.js.

Development

npm test
npm run check
npm audit --omit=dev

The test suite covers JSON sanitization, serialized command execution, drawing fingerprint validation, and isolated plugin installation without secret disclosure. Test presentation mutations on a disposable file before using them on important documents.

Current limitations

• The bridge acts on the presentation currently open in ONLYOFFICE. It does not yet bind mutations to an expected document path or fingerprint.

• Saving plugin-created changes is not fully reliable in ONLYOFFICE 9.0.3.

• undo only rolls back the latest object added by this bridge.

• Semantic text extraction from some presentation objects is incomplete.

License

GNU General Public License v3.0 only. You may use, study, modify and redistribute this project under the terms of the GPL. Distributed derivative works must remain available under the same license. See LICENSE.