X402 List MCP vs MCP Server

x402_check_health

Call this before you send a payment, or right after a call unexpectedly failed: is this service up right now. With no slug, the directory snapshot: five status counts across 500+ services (include_services=true attaches every row). With a slug: that service's status, its 24h/7d/30d/90d uptime windows, response time, consecutive failures, daily snapshots. No money fields.

x402_facilitator_volumes

Call this when the question is about the rail rather than the service: which x402 facilitator actually settles money, and how much. Returns on-chain-verified settlement volume and transaction counts per facilitator for today (UTC), 7d, 30d and all-time, plus a verification flag ('on-chain' once volume has been observed on-chain, else 'listed'), across more than 30 facilitators. Optional daily timeseries (up to 90 days) and per-chain breakdown. Volume is decimal USD. Caveats: PER-FACILITATOR, never per-service; the *_24h fields cover today (UTC) so far, not a trailing 24 hours, and reset at 00:00 UTC, so prefer 7d.

x402_assess_services

Call this when the free signals have run out: you hold 2 to 8 finalists from x402_search_services or x402_find_best_service, their stored fields do not separate them for YOUR stated need, and choosing wrong costs more than a quarter. It buys one fresh AI assessment reasoned against your question, not a cached grade; reading an already-computed assessment stays free via x402_get_service. Price: a one-time $0.25 USDC on Base, over two calls. Call once WITHOUT payment_signature_b64 to receive the x402 payment challenge verbatim (accepts[], amount, payTo, and a base64 PAYMENT-REQUIRED header); sign accepts[0] client-side with your own wallet; call again with the SAME question and services plus payment_signature_b64 to receive the report and a base64 PAYMENT-RESPONSE settlement receipt. This server holds no keys, never signs and never settles: it only relays the challenge. Optionally add probe { slug, endpoint_path? } to have one listed service paid and called for real and its answer analyzed: the challenge is then priced at $0.25 plus that endpoint price X, and the report gains a probe_report block with a verdict and truncated extracts, never the verbatim third-party body. When live probing is not armed the probe is ignored. Caveats: read the amount to sign from accepts[0].amount, never from a fixed figure, since a probe changes it; probe fees are non-refundable whatever the verdict; if the fresh run cannot be produced the server answers before settling, so you are never charged for nothing; there is no refund. Prices are US dollars.

x402_change_events

Call this before you trust anything you cached about a service, and right after a payment failed for no obvious reason: the monitor's log of what moved under you. Returns payTo, price and 402-schema changes observed on listed services, most recent first, in exactly three event types (payto_changed, price_changed, schema_changed). Filter with service (the slug), type, and days (1 to 365, default 90). Caveats: prices here are atomic token amounts, never dollars, and every payTo is masked by design, so the feed reports THAT the payout address changed, never the address. Free and read-only.