Upvotehall: a link aggregator for a programming community
Links and text posts ranked by votes and age, newest and top pages, threaded comments, karma and reply emails, all live.
Agent specs
- Agent
- Claude Code, Opus 5.5 Medium
- Time
- 16 min
- Cost
- $4.99*
Agents work faster and more accurately on Elements.
* Cost at API rates, September 2026.
Run it yourself
Paste this prompt into your AI agent. You get the finished app on your own machine, ready to change however you like.
Install elements: curl -fsSL 'https://install.elements.dev?os=darwin' | sh && export PATH=~/elements/bin:$PATH Create an Elements app from the elementscode/demo-upvotehall scaffold: cd ~/elements/projects elements create upvotehall -scaffold=elementscode/demo-upvotehall cd upvotehall Start the app.
How it's built
Upvotehall needed votes that move scores on every open page, a front page ranked by votes and age, live threaded comments, and an email when someone replies. Each of those is a part of Elements, so the agent spent its 16 minutes on the community itself.
What Elements gave the app
- Live posts and scores. Posts are a LiveTable opened by rank for the front page, by time for newest and by author for profiles, 25 at a time. Database triggers keep each post's score and comment count, and a notify trigger carries every change to the open lists.
- Votes through a view. Votes are LiveTables opened for the signed-in reader, so a vote is an insert or delete through the view, with the voter set from the session.
- Live threads. Comments are a LiveTable opened per post. A new comment appears in every open copy of the thread and schedules its reply email in the same transaction.
- Ranking on a schedule. A SQL function scores each post by votes and age, and one cron line runs a job every five minutes that re-ranks the last two weeks, so the front page keeps moving.
- Reply emails and karma. A background job emails the author of the parent comment or post. A profile's karma counts the votes other people gave that user's posts and comments.
- Data from SQL files. Two migrations define the schema and its triggers, then seed eight users, thirty posts over the last four days, votes, and comment threads several levels deep.
What the project server gave the agent
The project server runs alongside the agent and answers as soon as a file is saved: it type-checks the templates, TypeScript and SQL, applies migrations and reruns the tests, so every question came back right away and the agent kept building.
What shipped
The app type-checks with zero errors and all 35 tests pass. Every page works on desktop and phone, and live updates arrive across tabs, such as votes, scores and new replies.
The code
Build it from scratch
To watch your agent build this app from an empty project, use the prompt we used instead. It takes longer than starting from the finished app above.
Install elements: curl -fsSL 'https://install.elements.dev?os=darwin' | sh && export PATH=~/elements/bin:$PATH Create an Elements app: cd ~/elements/projects elements create upvotehall cd upvotehall Start the app, then build this: Build a link aggregator named upvotehall for a programming community. - Sign up, log in. - Submit a link with a title, or a text post. - Front page ranked by votes and age, recomputed every few minutes; a newest page; a top of the week page. - Upvote posts and comments. - Threaded comments, collapsible, with replies to any depth. - User pages with karma, submissions and comments. - Reply notifications by email. Seed eight users, thirty posts over the last few days with votes, and comment threads several levels deep. Show the seeded logins on the sign-in page. Votes and new comments update in real time.
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