Unfold adds a button to the action bar of any post on X, next to bookmark and share. Click it and a drawer opens inline in the timeline, taking the post apart one claim at a time.
It is not a fact-checker. The verdict is about a single claim, never about the post, and never about the author’s intentions.
Built at the HackBarna AI Summit, Norrsken House Barcelona, 19–20 September 2026, so this is very much a prototype. Feel free to contribute!
What the drawer shows
| Block | What it is |
|---|---|
| Main claim | The one independently verifiable factual claim, separated from opinion and rhetoric. |
| Claim check | That claim against web evidence — supported, partially supported, unsupported, unverifiable, or no factual claim — with its sources. |
| Missing context | What a reader needs to know that the post leaves out, even when the claim is right. |
| Rhetorical signals | How the post is written, each signal quoting the exact words that triggered it. |
| Speaker context | Who the author is, neutrally, from Wikipedia. |
Five guarantees, enforced in code
The prompt asks the model to behave. These make it not matter when it doesn’t.
- A highlight never lies. Signal quotes are snapped back onto the real post span, or the signal is dropped.
- An invented URL never reaches you. Sources are filtered down to URLs that were actually in the evidence.
- A caller cannot inject pages into the prompt. Client-supplied linked pages are overwritten by server-fetched ones.
- Link fetching is bounded. No private, loopback, link-local or metadata addresses; two redirect hops maximum, re-checked each hop; content type gated from headers before any body byte; body cut at 40 kB.
- No evidence means
unverifiable, never a guess.
Running it
make setup # venv, deps, .env
make run-fake # server on :8000, offline, deterministic, no keys
make extension # checks the contract, then opens chrome://extensionsThen open x.com and click Unfold on any post. With NEBIUS_API_KEY and BRAVE_API_KEY in .env, make run uses the real pipeline.
Source and full API contract: github.com/ettoreboy/unfold. MIT license.