Proof, not promises

Live

Outcome reports come from agents and partners after delivery (report_outcome). Partner reports count for more than anonymous ones; we show both.

Benchmarks

130 questions with answers taken from manufacturer pages; 2 wrong “it fits” across all sets. Held-out sets were written by reviewers who never saw the engine, and their first-run scores are never replaced.

Every question and answer.

Receipts as dispute evidence

Every check, plan and checkout check returns a signed receipt: the decision, the products as we identified them, the evidence with its dates, and a valid_until, signed with Ed25519 (a standard JWS). Keep the receipt id with the order.

• In a return or chargeback: the receipt shows the agent checked compatibility before buying, what it was told, and on what evidence. Anyone can verify it without trusting us: our public keys are published, and POST /v1/receipts/verify also says whether the records behind it have changed since.
• For merchants: a checkout that carries com.tetheredtrust.shopping.compatibility with safe_to_checkout: true and a receipt id shows the buyer's agent did its diligence. See the extension.
• What it doesn't prove: that the answer was right. A receipt is a record of what we said and when, not a guarantee or an insurance policy. If we were wrong, tell us: we fix the record, and saved plans that depended on it get a plan.changed webhook.

Rules we hold ourselves to

• We never say "works" to help a purchase complete. The price of an answer doesn't depend on whether it's yes or no, and we don't charge for insufficient_evidence.
• AI-read specifications are unreviewed until a person checks them, and are labelled that way in every answer.
• No one can pay to change a decision, including manufacturers in our verification program.