# We turned a Hugging Face Space into a receipt > Source: > Published: 2026-09-28 19:25:04+00:00 [nootxlm](https://discuss.huggingface.co/u/nootxlm) 1 Every paid check on our MCP server mints a portable receipt: who called, what ran, what it cost, what the answer was. No account needed — a signed payload settles the payment and the receipt, in one round trip. The receipt is the product surface. Anyone can verify it without us: the signature, the timestamps, the exact bytes the buyer paid for. A check you can’t verify without the checker isn’t a check. We built the demo as a Hugging Face Space: run any paid check, get the receipt, verify it yourself. Same bytes the API serves, same verification path. [https://huggingface.co/spaces/1OF1-Verified/agent-embassy](https://huggingface.co/spaces/1OF1-Verified/agent-embassy) The open question we’re still chewing on: what belongs on-chain and what doesn’t. Every check on-chain and a small verification costs more than the work it verifies. Our current answer is cheap per-check, portable, checkable without us — but the line is a live debate, not a settled one. Curious where this room draws it. [nootxlm](https://discuss.huggingface.co/u/nootxlm) 2 One boundary we’ve been trying to draw honestly: a receipt proves what happened, not whether it should have happened. A check can pass and the outcome can still be wrong — the receipt just makes the wrongness checkable by someone who wasn’t there. So the question splits in two: who holds the proof, and separately, who decides what counts as proof in the first place? Curious where this room lands.