Live-Payload Conformance Probes

An MCP server's declared schema is a hypothesis until a probe checks it against the real upstream. In the documented evidence case, a server declared 9 fields and live responses carried 4; zero records came back as HTTP 404 and were read as "server broken"; a 300-page exhibit returned its first 50 pages labelled "complete" — and the same failure classes survived eight months across four production servers before a manual audit found them. This service runs those probes continuously: live upstream payloads are sampled and diffed against the server's declared schema (field presence rate, population rate, type checks), and every sampled result gets a receipt an agent can branch on: ABSENT (legitimately no data) vs EMPTY vs PARTIAL (with expected-vs-received counts — the count check overrides any upstream "complete" label) vs COMPLETE vs BROKEN, digest-chained and Ed25519-signed. Operators are alerted when a field's presence/population rate moves against baseline. Proven in the lab: 16/16 tests over real HTTP on the evidence shapes; receipt-driven branching changed on all three evidence cases; measured compute ~$0.000000002/probe.

Prices

• Per-result receipt check $0.01/check (x402) — one live-payload conformance check against a registered declared schema + one signed receipt. Metered from the first check.
• Server Operator $9/mo per operator — up to 20 tools, 6-hourly probing included, drift alerts; probes above the included cadence $0.002/probe. First month free for the first server, one time per operator.
• Fleet / Registry $29/mo per operator — up to 200 tools, daily probing included, conformance-score surface; probes above the included cadence $0.002/probe.

Start

Machine surface: https://textforagents.com/products/live-payload-conformance-probes/ — POST /register {account_name, payer_wallet} → per-customer token (shown once). POST /registrations registers your declared schemas and upstream bases (public addresses, or your own internal wrapper under an explicit grant; upstream credentials are encrypted at rest and revocable). POST /check runs the $0.01 paid check; POST /trial claims the one-time free month; POST /subscribe {tier: "server"|"fleet"} starts a plan; POST /probe runs a cadence probe; GET /scores/<registration id> is the public conformance-score surface. MCP JSON-RPC at POST /mcp (tool: conformance_check). Product-owned demo fixtures under /fixture/ reproduce every verdict class. Receipt signing keys are published at GET /public-key and any receipt verifies at POST /verify-receipt. Docs: /docs, /openapi.json, /llms.txt, /terms, /privacy, /.well-known/x402 under the product path.

Limits (stated plainly)

• A receipt describes the live payload observed at probe time only; it does not certify an upstream API or warrant future payloads.
• The lab's measured cost is the compute leg only (~$2.1e-9/probe); upstream fetch latency, egress, and rate limits dominate at scale and are measured in the product's production monitoring record.
• Credentialed-wrapper baselines are built per wrapper class from operator-granted credentials; a class is covered once its baseline exists.
• Payload size cap 64 KiB; per-server rate cap 120 probes/minute.

Support: support@textforagents.com · Provider: TextForAgents LLC