Pi-Stack

We build AI products and keep them running.

Pi-Stack is the studio behind DebateLab, an AI debate coach for students. Claude Sonnet 5 and Opus 5 power DebateLab Pro, and Claude Code builds it.

Open DebateLab See everything we've shipped
Chorelychorely.pi-stack.org
YubiNotesnotes.pi-stack.org
ProtoPiproto.pi-stack.org
Escuchaescucha.pi-stack.org
Athelathel.pi-stack.org
DebateLabdebate.pi-stack.org

DebateLab

Students pick the motion they're preparing, build cases for both sides, and practise against the AI. Everything they make is saved to that debate.

debate.pi-stack.org
DebateLab home page with the case generator open on the motion 'Should schools ban phones?'
Models
Claude Sonnet 5 by default on Pro, Claude Opus 5 for the hardest work.
Languages
English, Spanish and Hungarian, in both the interface and the AI's answers.
Platforms
Web, an installable app that works offline, and iOS.
Plans
Basic and Pro through Stripe. Pro is $5 a month, with a 3-day free trial.

Prepare

  • Generatebuilds a full case for either side.
  • Brainstormexplores angles on a motion.
  • Factoidsfinds cited evidence.
  • Flowchartmaps claims and rebuttals.

Practise

  • Attackfinds the weak points in your case.
  • Askis a streaming debate coach.
  • Crossfiredrills questioning.
  • Sparringruns a timed round against the AI and scores it.

All in on Claude

Claude is the model our students argue with and the engineer that ships our code.

In the product

  • Claude Sonnet 5 is DebateLab's default Pro model, and the fallback whenever our router isn't sure which model fits.
  • Claude Opus 5 takes the work that needs the most judgment: nuanced rhetoric, adversarial critique and long-form cases.
  • Next: Claude on every plan, so Basic and trial students practise against it too.

In how we build

  • Claude Code writes most of our code, across DebateLab and everything else on this page.
  • Every DebateLab change goes through CI, review and a staging deploy before it reaches production.
  • ProtoPi exists so our coding agents can put a prototype in front of us as a link to review.
Claude Opus 5Claude Sonnet 5Claude Code

More we've shipped

Everything here is live on pi-stack.org.

Title screen of The Underwater City of Athel, an illustrated cutaway of a city under a glass dome
Interactive story

The Underwater City of Athel

An illustrated story about Mira and a city of glass beneath a sky no one is allowed to see. Every choice moves her toward one of three endings.

Read Athel
Escucha home page for Colegio Internacional Torrequebrada, in Spanish, explaining how to send a confidential report in three steps
Client project

Escucha

A confidential reporting channel for the community of Colegio Internacional Torrequebrada, in Spanish and English. Students share a concern without giving a name, then check the school's reply with a private code.

Visit Escucha

ProtoPi

Coding agents deploy HTML prototypes to a shareable link, and people leave comments on them.

proto.pi-stack.org

YubiNotes

Notes that only open with a YubiKey, with wikilinks, tags and a live Markdown editor.

notes.pi-stack.org

Chorely

A chore tracker where kids earn tokens toward rewards. It runs in the browser and keeps the data on the device.

chorely.pi-stack.org

Talk to us

Questions about DebateLab, partnerships, or anything on this page go straight to Adam.