Who it’s for
Whatever you’re writing,
you don’t have to do it alone
Tandem is a plain Markdown editor first. The co-author is there when a draft gets stuck, a sentence runs long, or you just want a second read.
Essays & articles
A line editor who works in the margin
Draft long-form the way you always have. When a paragraph feels heavy, highlight it and let Claude suggest a tighter version — then take it or leave it.
- Trim wordy sentences without losing your voice
- Catch the claim you can't quite back up
- Keep an eye on structure as the piece grows
Studying & notes
Turn reading into understanding
Paste your notes, then ask for the gaps. Claude flags what's missing, offers the counterargument, and gives you the plain-English version when the source won't.
- Ask for the counterpoint you didn't consider
- Spot the gap before the exam does
- Rewrite dense passages in plain language
Docs & READMEs
Keep technical writing honest
Walk through your own setup steps with a skeptic reading along. Claude flags the instruction that quietly assumes too much and tightens the rest.
- Flag steps that won't work as written
- Catch the assumed prerequisite
- Trim a wall of text into something scannable
Reports & memos
Cut the padding, keep the point
Long documents drift. Highlight a bloated section and Claude proposes a leaner version. You stay in charge of what survives the edit.
- Shorten without flattening the meaning
- Find the buried recommendation
- Make the summary actually summarize
It’s the difference between asking someone to read your draft and actually handing them the pen — except you can take it back any time.
Open a file and try writing together
Free to download. Works on the files you already have. No account needed to start.