Developer Brandon Thomas has released WordCraft, GridCraft and DeckCraft, free open-source clones of Microsoft Word, Excel and PowerPoint written in the Rust programming language with assistance from Anthropic's Claude.

By the project's own figures, WordCraft covers 88% of Word's ribbon features and GridCraft handles 513 of Excel's 523 worksheet functions. Even so, the development team rates the apps only 50% to 60% ready for real-world work. The release follows Thomas's ArtCraft suite, which mirrored Adobe's creative applications, and takes aim at a Microsoft 365 subscription that costs $99.99 per year for a single user.

The pitch, in essence: pay roughly $100 every year for Microsoft Office online, or pay nothing for the AI-assisted “Office” clone that performs many of the same tasks and runs fully offline.

From Adobe to Microsoft

Thomas, the engineer behind the ArtCraft project, published the three applications on GitHub as WordCraft, GridCraft and DeckCraft. As open-source software, anyone can read, copy and modify the code, and the MIT and Apache 2.0 licenses permit reuse even in commercial products.

Earlier this month, Thomas drew wide attention with ArtCraft, a set of free applications mirroring Photoshop, Illustrator, Premiere and Lightroom, built with Claude Opus 5.5 after Adobe charged him its cancellation fee one too many times. The project landed amid a broader wave of AI cloning that has seen a developer get Grand Theft Auto V running natively on an iPhone and modders pit Minecraft creepers against an Elden Ring boss. The Office suite applies the same recipe — a solo developer directing an AI model — to everyday productivity software.

Built in Rust, Clean-Room Style

The Office clones are written in Rust, a programming language known for its speed and for blocking the memory bugs that make software crash. A single codebase runs natively on Windows, macOS, Linux and BSD, and also inside a web browser.

Thomas calls the project a clean-room rebuild, meaning the apps were written from public file-format specifications and by observing how the originals behave, never by copying Microsoft's code. It is the same legal approach Compaq used to clone IBM's PC BIOS, the basic startup software of early personal computers, in the 1980s.

WordCraft: 88% of Word's Ribbon

WordCraft reads and writes .docx, Word's native file format, and covers 88% of the features in Word's ribbon, the strip of tabs and buttons along the top of the screen. Track changes, footnotes, citations and mail merge — the tool that pulls names from a spreadsheet to personalize hundreds of letters — are already implemented.

Counting file fidelity and stability, however, the team estimates WordCraft is only about 60% of the way to replacing Word for real work. It remains labeled alpha, an early test version in which bugs come standard.

In hands-on testing, Decrypt found the app weighs just 91 MB, feels snappy and looks almost the same as regular Microsoft Word, suggesting it can easily cover everyday office jobs in place of the premium suite.

GridCraft and DeckCraft

GridCraft, the Excel clone, already handles 513 of Excel's 523 worksheet functions — the formulas such as SUM or VLOOKUP that make spreadsheets do math — plus 89% of its ribbon commands. Its own developers rate it about 50% ready for real work, with compatibility on real-world .xlsx files next on the to-do list. In other words, it knows almost every formula but may still trip over a company's budget spreadsheet.

DeckCraft, the PowerPoint stand-in, covers about 79% of PowerPoint's features and 93% of the core ones, according to its GitHub page. It opens and saves .pptx files, runs transitions and animations, and exports to PDF, but it has not yet reached its first alpha.

Every Button Is an Agent Command

Every button in all three apps doubles as a command that an AI agent, a model that takes multi-step actions on its own, can trigger. The apps plug in through MCP, the Model Context Protocol, a standard Anthropic created so AI models can operate outside tools. In practice, a user could ask Claude to build a chart in a spreadsheet or reformat a report without touching the mouse — a design that makes the suite drivable by software as much as by hand.

A Direct Shot at the Subscription

Microsoft charges $99.99 per year for Microsoft 365 Personal and $129.99 for the family plan, which is how most households get Word and Excel today. A free look-alike that opens the same files is a direct shot at that bill. Part of what sustains that bill is compatibility: .docx, .xlsx and .pptx are the file types offices and schools already exchange, which is why real-world file testing sits near the top of the clones' to-do lists.

Free Office alternatives have existed for decades: OpenOffice.org was born when Sun Microsystems released the code of its StarOffice suite in October 2000, and LibreOffice split off from it in 2010. Both took years of work by large developer communities, while Thomas shipped his three apps less than two weeks after the Adobe clones, working with an AI model.

The suite's design closely resembles Microsoft Office, so heavy users should not struggle much with the switch — historically the main barrier preventing people from changing software providers.

The Model Behind the Clones

The model behind ArtCraft, Claude Opus 5.5, launched September 22 at $4 per million input tokens and $20 per million output tokens; tokens are the chunks of text an AI reads and writes, and the unit by which AI companies bill. On Terminal-Bench 4.0, which tests whether an AI agent can finish complex professional tasks in a command-line environment and scores the share of tasks completed, Opus 5.5 hit 66.4%.

Overpromises and GitHub Stars

Thomas also has a habit of promising more than his apps deliver, at least so far, and has already walked back his pledge to match Adobe's feature set within a month. Developers do not seem to mind the wait: WordCraft had collected more than 12,000 GitHub stars, the platform's version of a bookmark, as of Wednesday.

Before a beta, the roadmap says WordCraft still needs testing against real-world .docx files, charts and SmartArt that survive save, page layout closer to Word's, a stability sweep and native printing. That checklist is the concrete near-term yardstick for the project, since clearing it is what moves WordCraft from alpha to beta.

Source: Decrypt