An editor where you and an AI work on the same document at the same time.
Tandem is a document editor that lets you and an AI work on the same file together. You highlight a passage. The AI sees what you highlighted and can ask about it, comment on it, or propose changes that appear as cards beside your document. You decide what to keep.
One thing to know up front: the AI side requires an MCP-capable AI client — Claude Code is the default — and the subscription behind it (for Claude, a paid Anthropic plan). Without one connected, Tandem is a capable local document editor and nothing more.
Tandem is approaching v1.0 and ships continuous improvements. See CHANGELOG.md for what is in the latest release.
Contents
What Tandem does
Most people use AI on a document by copying a passage into a chat window, asking a question, and pasting the answer back. Tandem closes that loop. The AI sits beside the document you are editing and reads from it directly.
When you highlight text, the AI sees the selection as you make it. You can ask it for a rewrite, a summary, a check on tone, or a second opinion. Its suggestions appear as cards next to the document. Accept them, set them aside, or reply to ask for something different.
Tandem is built to work with Anthropic's Claude out of the box. Other AI tools can also connect. See the developer section below for the details of which clients work and which are tested first.
See it in action
The main view. Your document fills the left side. The chat panel and any suggestions from the AI sit on the right.
A suggestion from the AI. Your current text and the proposed replacement appear together. Buttons let you accept the change or set it aside.
Who Tandem is for
- If you draft long-form writing and want a second reader for tone and structure.
- If you review documents — an essay, a thesis chapter, a report, or a contract — and want a faster pass.
- When a colleague hands you a document to mark up.
- When the AI wrote a draft and you need to decide what to keep.
Tandem is built for individuals working on their own documents. The example document types above are just that — examples; the workflow is the same whatever you are writing or reviewing. The interface is English-only for now.
Getting started
System requirements
Windows 10 version 22H2 or Windows 11. macOS 12 (Monterey) or later. Linux with glibc 2.31 or later (Ubuntu 20.04+, Debian 11+, Fedora 34+). On Windows, the first launch may show a "Windows protected your PC" warning until the installer's signing certificate accumulates SmartScreen reputation. See docs/troubleshooting.md#windows-smartscreen-warning for the steps to dismiss it.
Download the desktop app (recommended)
Pick the installer for your platform from the latest release. Windows, macOS, and Linux builds are available.
The desktop app bundles the editor, the server it talks to, and storage for the connection token. Updates land automatically. Double-clicking a .md, .txt, or .html file opens it directly in Tandem.
What you get
