A dropped subscription looks exactly like a quiet week. This service keeps the per-principal census the protocol draft omits, re-verifies every subscription on a stated cadence, and gives your agent a signed answer - with a freshness bound - to "am I still subscribed, and when was that last proven?"
The MCP Events draft makes permission re-verification a SHOULD with no interval and no conformance test, provides no server-side subscription listing, and allows no-expiry subscriptions - so a subscription can die silently (revocation, restart buffer loss, event-type removal) while the agent goes on believing it is watching, and a revoked one can go on delivering because nobody holds the index. This service is that missing layer, hosted and agent-callable: (1) a per-principal subscription census keyed (principal, server, event, arguments), so offboarding is one query and one revoke-all with proof; (2) bounded re-verification on a stated cadence, with reverified_at recorded per subscription; (3) flatline detection - a per-subscription expected-arrival baseline converts silence into a typed verdict (ALIVE / TERMINATED(reason) / UNREACHABLE / UNKNOWN), and silence degrades ALIVE to UNKNOWN, never to an invented TERMINATED; (4) zombie watch - where a delivery tap exists, deliveries after a recorded revocation mint a should-have-stopped receipt with the proven post-revocation count; (5) signed liveness receipts with an explicit freshness bound and the probe evidence attached - no grade travels bare - chained to the wake receipts your events produce.
Liveness verdict $0.01 (x402) · Metered attestation $0.25/subscription/mo (daily cadence included) · Operator plan $9.99/operator/mo (exactly 100 subscriptions at daily cadence) · sub-daily probes past the included daily tick meter at $0.01/probe, shown before enablement. One free liveness verdict per operator, ever.
Stated plainly, because the lab proved the boundaries: flatline precision is published as measured (factor-3 default: 16.7% of quiet exponential streams false-flag ALIVE to UNKNOWN, which costs a re-probe, not a wrong answer; silent drops are detected 99.7% by five mean intervals); the zombie watch requires a delivery tap - operator-declared subscriptions get census, probing, flatline, and receipts but no zombie watch, and are never described as having it; a real-network probe cost is unmeasured in the lab (localhost floor) and cadence metering is enforced; willingness to pay is unmeasured.
Support: support@textforagents.com