Rounder for developers

The engines behind roundertools.com also come as three free npm packages. They run on your own computer, in Node, with the same code the site runs in your browser: your files never leave the machine, and the packages make no network requests at all.

@roundertools/sdk: typed functions for Node.js, like pdf.compress(file, { target: '1mb' }).
roundertools: the command line, for scripts and batches: npx roundertools compress-pdf report.pdf.
@roundertools/mcp: an MCP server, so Claude, Cursor or VS Code can work on files on your computer.

Try it in 30 seconds

With Node 22.13 or newer, in a folder with a PDF in it:

terminal

npx roundertools compress-pdf report.pdf --target 1mb
npx roundertools list

To give Claude Code the same tools:

terminal

claude mcp add roundertools -- npx -y @roundertools/mcp --allow ~/Documents

What's included

29 tools in version 0.1: 12 PDF, 6 image, 7 video and audio and 4 file tools. The tool table lists each one with its command and function. Video and audio tools use the ffmpeg already installed on your computer; nothing of ffmpeg ships in the packages. Tools that need a screen (recorders, editors) or a model download (the AI tools) stay on the site for now.

Where things run

What	Where
Your files	Read and written on your machine only. Results go next to the input (or where you say) and never replace an existing file.
Network	None. The CLI and MCP server block outgoing connections in their own process as a safeguard.
PDFs and images	pdf-lib, PDF.js, qpdf and jSquash codecs, in-process (WebAssembly).
Video and audio	Your own ffmpeg, run as a separate program.
AI assistants	See only the paths, sizes and summaries the MCP server returns, plus text you ask it to extract.

License

The packages are MIT-licensed, so you can use them in any project, commercial or not. The website itself stays AGPL-3.0. The source for both is on GitHub, in packages/.