Describe it once.
It settles either way.
t3rn runs no fills of its own. It is the enforcement kernel: a standardized way to put virtually any operation — a transfer, a contract call, an agent job, a paid response, a standing subscription — under reversibility insurance. The escrow releases on proof or refunds on failure, and every ending, including the reverts, writes a receipt.
Read directly from public endpoints, not from anything we keep. The last tile is the argument for this whole surface: most observed agent work never completes, and a slice of what settles is graded by nobody. Any tile that cannot reach its source says NEEDS COUNTER rather than showing a number we made up.
Anything describable is settleable.
Describe the operation once. The settler escrows it, the layer decodes it, a referee grades it against a spec sealed before work started, and the money either releases or refunds. Either ending writes a receipt anyone can recheck without asking us.
That sentence is the whole product. What changes between a cross-chain transfer, an agent job, a paid API response and a standing subscription is only the evidence lane — not the grammar, not the escrow, not the outcome set.
Five properties, or a typed refusal.
An operation can go under the settler only if it has two accountable parties as attestation references, an acceptance spec sealable upfront as a digest, at least one evidence lane the layer can decode, a deadline in epochs with a grace rule, and a refund path.
Miss one and the API refuses with UNINSURABLE_PROFILE naming the property that is missing. That refusal is the standardization: it is what makes any operation a precise set rather than a slogan, and it is why anything whose 'done' cannot be sealed as a digest before work starts is refused by design.
Insurance without integration.
For any operation whose evidence lane is the chain itself, the buyer can route value through the gate unilaterally and insure the operation without the service's cooperation, its SDK, or its knowledge. The worker delivers exactly as it always has; the layer decodes the destination event; settlement happens buyer-side.
So the insured party integrates the record, not the insurer. A service does not have to join — it has to be decodable. And a service watching premiums flow on its own traffic without earning the vendor point has one rational move: enroll, and take the split.
No new operations. Ever.
Every verb here lands in the receipt-backwards table: an operation exists only if it produces a field of the receipt, or reads one. A profile that would need an operation the table lacks is a spec bug, not a feature request.
The capture doors follow the same rule. A log-stream sink, a workflow node, owner-keyed polling and a tool an agent calls are four transports for the same two calls. Anything that cannot be replayed from sealed evidence is not an operation, it is a liability.
Returns the derived terms: bond floor, premium quote, available referee lanes, cover capacity left. Promises nothing forward and expires with the meter epoch.
Declares the job and locks the escrow through the gate. The acceptance digest seals here — before work starts, never after.
Requests the verdict. The referee grades against the sealed acceptance and the resolution engine computes the outcome. Nobody votes.
Needs nobody's goodwill. Past deadline plus grace the default is revert, the refund pays the refund path, and a receipt records it. Funds cannot strand.
Free, keyless, forever. Never wrapped by any skin. The check anyone can run without us is the product.
Every mutating verb is idempotent by client key and refuses in a typed register. verify is free, keyless, and never wrapped by any skin — the check anyone can run without us is the point of the whole machine.
Cheating is negative-expected-value exactly when the bond clears the frontier. The shipped default b = 10p deters any referee catching more than one cheat in eleven — and q is now measured per kind and lane from the decoded tape, not assumed.
The refund plus the bond. Being cheated is, ex post, the victim's best financial outcome, which is what makes cheating pointless ex ante.
The worker's bond is first loss; the book pays only the residual when a bond is undersized. A flat premium cannot fund full-value primary cover, so residual is the only honest shape — the backtest is unambiguous about this.
If a censored evidence lane counted as the worker failing, buying a blind spot would be a profitable short. It voids instead, and the money is held. Nobody earns from darkness, so nobody buys it.