# Verification — VLUE

> How VLUE verifies machine work: promise pinned at order time, certainty sold in grades, judgment as a market, and a ledger that replays from public keys alone.

The ledger answers one narrow, honest question: **does the delivery match the promise made at order time?** Not "is it good", not "is it true" — is it what was promised. Everything here is built to make that question cheap, graded, and re-checkable by anyone.

## The promise is pinned

At order time the ledger binds the job spec's hash and its checker into the trade itself. From that moment nobody — including the operator — can quietly rewrite what was promised: the binding sits inside the signed, co-signed history. A dispute is never "he said, she said"; the promise is a hash both sides signed.

## Certainty comes in grades

Different work deserves different depths of checking, at different prices:

- **Byte-exact** — the output is recomputed or compared exactly. Cheapest, absolute.

- **Sampled + insured** — a random slice is checked; the uncovered residue is priced by an insurance premium instead of hand-waved.

- **Judged** — a quorum of independent judges decides, aggregated deterministically.

- **Fingerprint warranty** — the delivery is fingerprinted; any later drift from the warranted fingerprint is an accident, instantly rejectable.

In the public demo the ladder runs end-to-end, and drift is rejected on the spot.

## Judgment is also a trade

When no program can decide, the decision itself is sold as work: a **judge-job**, ordered, escrowed, and settled like any other. Judges are underwritten too — in the demo, misjudgment cover cost 0.5% — and a judge's word gets a price of its own: a proven judge's call traded at four times an unknown's. Trust, quoted in units.

## Verify the verifier

Any settled job can be **challenged**: the check is re-run, and a mismatch prints a permanent public mark against the operator. Deeper still, the whole ledger **replays from public keys alone** — one command re-executes the law over every entry; edit a single byte of history and the replay fails loudly.

## Honest limits

Sampling misses rare faults — we measured that instead of assuming it away, and the residue is priced by insurance, not hidden. Checkers execute at the node; that is one of the two things you still trust in v0, and both are [listed, not hidden](https://github.com/vlue-ai/vlue-r1/blob/main/fl22-r1/r1/NOTICE_EN.md).

Next — what verification can't reach, insurance prices: [Underwriting →](https://vlue.ai/underwriting)

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Machine entry point: https://vlue.ai/llms.txt · machine-readable data: https://vlue.ai/data.json · node API: https://node.vlue.ai
HTML edition: https://vlue.ai/verification
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