com.acjlabsPublished by acjlabs.comOfficial publisherv0.1.0Updated Oct 27, 2026
Checks x402 Bazaar resource listings against the public discovery catalog and flags drops.
The publisher's own server: Catalog Attribute Normalizer
Remote MCP server that checks whether an x402 seller's resources still appear in Coinbase CDP's public Bazaar discovery catalog.
Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.
Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.
Read https://sourceweft.com/mcp/com.acjlabs%2Fx402-listing-monitor/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.Add this to your client's mcpServers config.
{
"mcpServers": {
"x402-bazaar-listing-monitor": {
"type": "http",
"url": "https://x402-listing-monitor.acjlabs.com/mcp"
}
}
}Scheduled watchdog for x402 sellers: polls Coinbase CDP's public Bazaar discovery catalog for the resources you register and alerts when one drops out or comes back — instead of finding out from a revenue dip days later.
Sellers who settle real x402 payments have no reliable way to confirm their resources stay
discoverable in CDP's Bazaar catalog. The discovery API has a recurring, publicly-reported class of
bug where a resource silently stops appearing despite confirmed settlements — sellers currently catch
this only by manually re-running GET /discovery/merchant?payTo=<address> on their own schedule.
This service automates that check: register your payTo address and the resource URLs you serve, and
a scheduled poll diffs them against the live discovery catalog. State changes are recorded with
timestamps, so you have a durable history you can cite if you need to escalate to CDP support.
Endpoint: https://x402-listing-monitor.acjlabs.com/mcp (streamable HTTP)
One tool — no signup, no API key:
check_listing_healthChecks whether a seller's x402 Bazaar resources are currently listed under a given payTo address in
the public discovery catalog. Runs the same per-seller diff as the scheduled poller, on demand, for
any payTo/resources pair — registered here or not.
Returns each resource flagged as listed or missing, as JSON.
Base URL: https://x402-listing-monitor.acjlabs.com
POST /registersellerId — 2–64 characters: letters, digits, -, _payTo — 0x-prefixed, 40 hex charactersresources — 1–200 http(s) URLs, no duplicatesalertWebhookUrl — optional. A public https URL; alerts on your plan are POSTed to it. IP-literal,
loopback, .internal/.local hosts and URLs carrying credentials are rejected.alertEmail — optional, and stored but not yet used: email delivery is not enabled (see Status).Both contact fields are optional and registration succeeds without either. Supply neither and nothing is
pushed to you — use GET /status below to check on your listings yourself.
Resources are watched by self-declaration: the service checks what you tell it to check. A sellerId
that already exists is rejected rather than overwritten.
GET /statusReturns your own record: every resource you registered with its current status (listed, missing,
payTo-mismatch, or null if no poll has reached it yet), its consecutive-miss count and last-checked
timestamp, plus your most recent alerts and whether each was delivered.
Both sellerId and payTo are required and must match your registration; anything else returns 404.
This is a knowledge check, not authentication — the data it returns is a diff against a public catalog.
Your alertEmail and alertWebhookUrl are never echoed back, only reported as set or not set.
POST /pollRuns the same poll the six-hourly cron runs, immediately, for every registered seller. Takes no body and returns counts only:
It reports nothing about any individual seller. This endpoint is unauthenticated, so anything it
returned would be public — read your own state with GET /status instead.
Only one poll runs at a time. If a poll is already in progress — whether someone else triggered it or
the six-hourly cron did — this returns 409 and does no work:
That is not an error to retry through: the poll you asked for is already happening, and retrying cannot
make its alerts arrive sooner or arrive twice — the lock is what stops two concurrent polls from sending
you the same alert. It is a guarantee against duplication, not a delivery guarantee: an alert is always
recorded before it is sent, and if the send does not land it stays recorded and undelivered rather than
being retried. Wait, then read GET /status, which shows each recent alert and whether it was
delivered.
Per-IP rate limits apply to /register, /status, /poll and MCP tool calls.
checkedAt is the poll's timestamp, matching created_at on the same alerts in GET /status. Any 2xx
counts as delivered. Redirects are not followed — a 3xx is treated as a failed delivery, so register
the final URL. Failed deliveries are not retried; the alert stays in your history marked undelivered.
The scheduled poll runs every 6 hours. Each run diffs your registered resources against the live discovery catalog and records state changes with timestamps — a history, not just a point-in-time answer.
"Still missing" fires once per miss streak, from the first poll at which a resource has been absent
for three or more consecutive polls — long enough that indexing lag is ruled out. It does not repeat
every six hours while the resource stays missing; the current state is always readable from
GET /status.
Three consecutive misses is the earliest it can fire, not the only point at which it can. A resource that is already past three consecutive misses and has not yet been alerted for that streak raises its one alert on the next poll. If the resource recovers and later drops out again, that is a new streak and it alerts again.
Paid tiers also tighten the polling interval.
Early release. The service is live and polling, and the recorded alert history is authoritative for what it has observed.
https alertWebhookUrl and alerts on your plan are
POSTed to it when a check produces one.alertEmail is stored against your registration and nothing is
sent to it.GET /status gives you the same information on demand.This repository hosts the documentation for the hosted service. The service implementation is not open source. Bug reports and feature requests are welcome in this repo's Issues; you can also reach us at [email protected].
This repository hosts the documentation for the hosted service. The service implementation is not open source. Bug reports and feature requests are welcome in this repo's Issues; you can also reach us at [email protected].
Source: README.md at commit fe0213b
Checks whether a seller's x402 Bazaar resources are currently listed under the given payTo address in the public discovery catalog. Flags each resource as listed or missing — the same per-seller diff the registered poller runs on a schedule, run once on demand for a payTo/resources pair whether or not it has been registered with this service.
payTorequiredresourcesrequired90% of the applicable checks met
How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.
Declare a license in the repository or the registry entry.
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{ "sellerId": "your-slug", "payTo": "0x0000000000000000000000000000000000000000", "resources": ["https://api.example.com/your-resource"], "alertWebhookUrl": "https://example.com/hook"}GET /status?sellerId=your-slug&payTo=0x0000000000000000000000000000000000000000{ "polled": 2, "ok": 2, "failed": 0 }{ "status": "already_running" }{ "service": "x402-listing-monitor", "sellerId": "your-slug", "checkedAt": "2026-08-07T00:00:00.000Z", "alerts": [ { "type": "listing-dropped", "resource": "https://api.example.com/your-resource", "detail": "was listed, now missing from discovery", "message": "⚠️ Listing dropped: https://api.example.com/your-resource — was listed, now missing from discovery" } ]}