Back the people building real things with AI.
See who's shipping real work with AI — from their very first session, months before there's a deck. Real, tracked, impossible to fake. Find the outliers early, with proof, before anyone else does.
YC built Paxel to source founders exactly this way — reading their AI coding sessions. Promptbook gives that signal back to you, for every builder.
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“The star economy is a $50 problem with a $50 million consequence.”
— Theo Browne, developer & investor
Every signal you scout on is gamed or late.
Every legacy proxy for builder ability broke at once. Build telemetry — how someone actually ships with AI, captured at the source and tied to the person — is the one signal that didn't. Here's why the rest fail you.
A diligence liability.
~$85 buys the 2,850-star seed-stage median — a 3,500× return on fraud. ~6 million fake stars across 18,617 repos, AI/LLM repos the largest category.
Carnegie Mellon University, StarScout · ICSE 2026
Rewards charisma.
A deck rewards whoever presents best, not whoever ships best. By the time there's a deck, the edge is gone — and so is the price.
The deck arrives last — long after the work is visible to anyone watching.
Index companies after they form.
Harmonic, Evertrace and gitdealflow scrape external, gameable signals — stars, commit velocity, registries — attributed to a company. You see the builder once everyone else can.
Evertrace: “detect founders before they show up in any startup database.”
X-ray diligence — the read you usually develop in six months, before you write the check.
On any builder's profile you can see how many hours they've spent on a single project, across how many consecutive days, and which models they default to. How resourcefully they build — tokens and cost per session tell you whether a founder burns through compute or engineers efficiently. A builder shipping a production-quality build on $3 a session is a different bet than one burning $50 on a toy.
That signal exists nowhere else — and by the time you're in a data room, it's too late to use it. Every number is captured automatically from the terminal as they build, so unlike a pitch or a polished deck, it can't be performed for you.
Un-fakeable build telemetry, tied to the person.
Vibe coding exposed the gap between generating code and shipping. Promptbook shows who actually ships — tokens, build time, real shipped work, captured continuously from the terminal. Stars cost three cents. A 2-million-token build can't be bought at any price. YC built Paxel on exactly this signal to source founders; we capture it for every builder, and give it back to you.
Polywork raised $44.5M and died — self-reported data, and no buyer to give the profile a job. Ours is captured at the source, so it can't be faked, and you are the buyer — the supply compounds on its own.
Real builders. Verified output.
Before they're on anyone's radar.
These are real builders, here because their proof accrues passively — every session generates it whether or not anyone's watching. Every stat below is tracked, none typed in. 15.3K builds from 224 builders — and growing every day.
From thesis to first check.
No data-science team, no scraping pipeline. Set a thesis on real build axes and reach the builder directly — often before there's a company to scrape.
Filter to your thesis
Filter the whole pool on real axes — tokens, build time, builds, languages, the tools they live in. You set the bar; we never sell you a ranked match-score.
Surface the outliers
See exactly who clears it — the builders shipping hardest with AI, captured at the source, tied to the person, before they're on anyone else's radar.
Reach out first
Message the builder directly, while they're still just shipping. Get the warm intro before there's a deck, a domain, or a competing term sheet.
Back the real AI
builders early.
Source on proof, not stars. Filter the whole pool to your thesis and reach the builders who are raising or shipping hardest — direct, before there's a deck or a competing term sheet. One outlier you reach first pays for the seat a thousand times over.
Self-serve. Cancel anytime, billed securely by Stripe. Everything below is included.
- ✓Search the full builder poolFilter your deal flow on real, tracked work — tokens, build time, languages, active days, days-on-project. Find who's shipping hardest before they're on anyone's radar.
- ✓Post offers gated by real proofInvestment, co-founder, or collaboration. Set a threshold on tracked work — only builders who genuinely clear it can respond.
- ✓30 credit-DM invites / monthReach builders direct, gated by real tracked stats. Each credit is refunded the moment they reply — you only pay for conversations that start.
- ✓Your verified investor profile + directory listingA public page at /org/your-fund and a spot in the Organizations directory, so builders can see who's reaching them.
- ✓Saved thesis filters & tracked buildersKeep your filters and the builders you're following, ready to revisit.
Not affiliated with or endorsed by Y Combinator. Paxel and the GitHub fake-star figures (Carnegie Mellon University, ICSE 2026) are referenced as public category validation.