Provider: TextForAgents LLC. This service provides subscription liveness attestation: a per-principal subscription census, bounded re-verification on a stated cadence, flatline verdicts, zombie-watch receipts on tap shapes, and signed liveness receipts with explicit freshness bounds.
Prices: verdict $0.01/query; metered attestation $0.25/subscription/mo; Operator plan $9.99/operator/mo including exactly 100 subscriptions at daily cadence; probes past the included daily tick on a faster selected cadence meter at $0.01/probe, disclosed before the faster cadence is enabled. One free liveness verdict per operator, ever; after it, standard prices apply to all verdicts, attested subscriptions and plans. Payments settle in USDC on Base via x402 and are verified before work; bogus or replayed payments are rejected.
Limits you accept: Flatline precision, published as measured in the lab (bench_q2b, exponential arrival law, 600 trials/factor): factor 3.0 (default) false-flags 16.7% of ALIVE streams to UNKNOWN; silent-drop miss 3.7% at 4x mean interval, 0.3% at 5x, 0% at 8x. Silence degrades ALIVE to UNKNOWN (inviting a re-probe), never to a false TERMINATED. Boundaries, stated plainly: all receipt and observation times are server-stamped - caller-supplied timestamps are never used, so a freshness bound can only be earned by a real probe at a real time; freshness-bound verdicts only; the flatline error table above is the measured one and no other precision figure is stated; the zombie watch exists only on tap shapes (server-sdk / client-proxy) - operator-declared subscriptions get census, probing, flatline and receipts but NO zombie watch and are never described as zombie-watched; real-network probe cost was unmeasured in the lab (localhost floor only) and is measured in production per shape with cadence metering enforced; willingness to pay is unmeasured. Receipts decay by their own freshness bounds; a stopped service issues no new probes, verdicts or receipts and never silently extends a held receipt. Data retention: census, receipts and account records are retained 30 days after an attestation lapses, then pruned; backups are kept 30 days. Support: support@textforagents.com. No support promise beyond the documented limits is made.