“The paid run call returned an application error”

On 2026-07-27, I called redlynr.com's x402 API endpoint, `POST /run`, and bought its response for $0.001 in Base USDC. The advertised product was: Agent guardrail decision engine. Call once before every agent action; returns a single decision — proceed, slow down (with a reason and wait time), or stop — based on cost budget, chain depth, step cap and retry budget, and request volume pressure. Policy thresholds are configured separately via /policy; this endpoint only reports the decision for a single action.

{
  "agent_id": "agent_42",
  "chain_id": "chain_abc123",
  "is_retry": false,
  "step_cost": 0.02,
  "tenant_id": "acme_corp"
}

The payment settled and the request finished with HTTP 200 in 9.35 seconds. The returned product contained 122 bytes. Top-level fields included `error`. The Base settlement transaction was https://basescan.org/tx/0x9d1e426a2bcd12987227751a2c072e1912af9e483a43e17e0d58484db13e1d67.

A sanitized exact excerpt from the purchased response was:

{"error":"tenant_id is not registered — call POST /register first to claim your namespace and receive your owner_token"}

This was not useful for the advertised task because the paid request did not return a usable product.