Celo x402 Facilitator
org.celo/x402-facilitatorcelo.orgstreamable-httpv1.0.0Scanned
Check supported assets and verify x402 payments on Celo
5 tools: 1 do something that can't be undone and 4 only read.
- Reads private data · 0
- Reads text others write · 4
- Can send data out · 0
- 1 finding
Anlyon alternative
1 of these tools change something. Run those as governed actions.
Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.
Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.
Import an OpenAPI spec →Tools
Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.
5 tools
Can't be undone 1Claude Code: ask
verify_paymentCheck a signed x402 payment against its requirements: signature, amount, balance and simulation.Reads text others write1 finding
Why it is in this group
- The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Findings
- Warn
The server marks "verify_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
What this check looks forMatched text
annotations: {"readOnlyHint":true,"openWorldHint":true}; The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
Description, as the server wrote it Check a signed x402 payment against its requirements: signature, amount, balance and simulation. Moves no funds. Same answer as POST /verify, and it spends the same per-IP allowance.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: true
Only reads 4Show 4 read-only tools
get_configEvery settleable asset with its address, decimals, transfer method and EIP-712 domain values, plus the pricing model (gas at cost, plus a fee in basis points on the payment value w…No findings
Why it is in this group
- The name "get_config" says "get": a word for reading.
Description, as the server wrote it Every settleable asset with its address, decimals, transfer method and EIP-712 domain values, plus the pricing model (gas at cost, plus a fee in basis points on the payment value when the asset has a USD price), the gas fallback and the free-credit allowances. Same answer as GET /api/config.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false
get_healthWhether the facilitator behind this host is answering.Reads text others writeNo findings
Why it is in this group
- The name "get_health" says "get": a word for reading.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it Whether the facilitator behind this host is answering. Same answer as GET /health.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: true
get_supportedThe (x402Version, scheme, network) kinds and extensions this facilitator verifies and settles.Reads text others writeNo findings
Why it is in this group
- The name "get_supported" says "get": a word for reading.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it The (x402Version, scheme, network) kinds and extensions this facilitator verifies and settles. Same answer as GET /supported.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: true
payment_statusWhether a signed payment authorization has been used on chain, for a client whose settle reply was lost.Reads text others writeNo findings
Why it is in this group
- The name "payment_status" says "status": a word for reading.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
- untrusted-inputThe description's first sentence says "reply": it reads comments, which other people can write.
Description, as the server wrote it Whether a signed payment authorization has been used on chain, for a client whose settle reply was lost. Answers unspent, consumed or expired from the chain (EIP-3009 authorizationState, or the Permit2 nonce bitmap). unspent is not final: the authorization can still be used until validBefore, and a settlement already in flight reads as unspent here. Only consumed and expired are final; expired is only reported 5 s after validBefore, so a payment still in flight is not called final. The settled and pending states need the owning API key and are only served over HTTP. Same answer as GET /settle/status, and it spends the same per-IP allowance.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: true
This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.
Exfil surface
Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.
No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or outbound.
- Reads private data0
- Reads files, mail, messages, databases, secrets, calendars or repositories.
- Reads text others write4
- Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
- Can send data out0
- Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.
Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.
Findings
Matches of fixed checks, with the text they matched.
- Warnverify_payment
The server marks "verify_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
What this check looks forMatched text
annotations: {"readOnlyHint":true,"openWorldHint":true}; The name "verify_payment" says "payment": a word that usually means money moves, which cannot be taken back.
History
Changes to its tool definitions and to its remote endpoint, newest first.
No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.
Install
Pinned to version 1.0.0. Values in angle brackets are yours to fill in.
claude mcp add --transport http x402-facilitator https://api.x402.celo.org/mcpclaude mcp add --transport http x402-facilitator https://api.x402.celo.org/mcpRun in a terminal.
Claude Code permissions
Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.
{
"permissions": {
"allow": [
"mcp__x402-facilitator__get_supported",
"mcp__x402-facilitator__get_config",
"mcp__x402-facilitator__get_health",
"mcp__x402-facilitator__payment_status"
],
"ask": [
"mcp__x402-facilitator__verify_payment"
],
"deny": []
}
}Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as x402-facilitator. Review it before you use it.
Capability tags behind 4 rules
- mcp__x402-facilitator__get_supported untrusted-input
- mcp__x402-facilitator__get_health untrusted-input
- mcp__x402-facilitator__verify_payment untrusted-input
- mcp__x402-facilitator__payment_status untrusted-input
Pin
Keep the decision: fail CI when the tools change, follow every change, or show a badge.
Pin in CI
Fail a build when the tools you reviewed are not the tools the server serves today.
curl -s "https://anlyon.dev/api/v1/servers/org.celo/x402-facilitator/verify?hash=fcb9a174785d85035f69cc7023f0a77b06c0d91834ab179a0280a2ed24337e77" | jq -e '.changed == false'Pinned hash fcb9a174785d, from Oct 27, 2026, 21:18 UTC.
Watch
Get told when its tools change: a new tool, a new description, a new class.
https://anlyon.dev/servers/org.celo/x402-facilitator/changes.xmlAn Atom feed. Works in any feed reader or Slack's RSS app.
Badge
[](https://anlyon.dev/servers/org.celo/x402-facilitator)Source: MCP Registry. Synced Oct 27, 2026, 21:18 UTC.