Base USDC Payment Verifier (x402)

com.onrender.x402-usdc-verify/base-usdc-verifierx402-usdc-verify.onrender.comstreamable-httpv1.2.0Scanned 1 hour ago

Verify a Base tx is a confirmed native-USDC transfer to a recipient. Paid via x402, 0.01 USDC/call.

2 tools: 1 do something that can't be undone and 1 only read.

Reads private data · 0
Reads text others write · 1
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.

2 tools

Can't be undone 1Sends, pays, publishes or merges: once done, it cannot be taken back.Claude Code: ask

verify_usdc_paymentVerify a Base (mainnet, default) or Base Sepolia transaction is a successful, confirmed transfer of native Circle USDC (not a look-alike token) to an expected recipient for an exac…Reads text others write1 finding
Why it is in this group
- The name "verify_usdc_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_usdc_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
  Matched text
  annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The name "verify_usdc_payment" says "payment": a word that usually means money moves, which cannot be taken back.
  What this check looks for
Description, as the server wrote it
Verify a Base (mainnet, default) or Base Sepolia transaction is a successful, confirmed transfer of native Circle USDC (not a look-alike token) to an expected recipient for an exact or minimum amount. Checks receipt status, canonical block, confirmations, optional payer, notBefore/maxAge windows; returns verdict valid|invalid|pending|not_found with machine-readable reasons and the matched Transfer log. Not charged on 4xx/5xx errors. PAID: 0.01 USD in USDC per successful call via x402 (eip155:8453). Malformed input is rejected before payment.
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: true

Only reads 1Looks things up and changes nothing.Show 1 read-only tool

get_pricingFree.No findings
Why it is in this group
- The name "get_pricing" says "get": a word for reading.
Description, as the server wrote it
Free. Returns the x402 price, network, USDC asset, payTo address and facilitator for the paid verify_usdc_payment tool.
Annotations the server declares
- readOnlyHint: true
- openWorldHint: false

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 write1: Brings in text someone else can write: web pages, inbound email, messages, issues and comments.; verify_usdc_payment
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.

1 warn

Warnverify_usdc_payment
The server marks "verify_usdc_payment" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
Matched text
annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The name "verify_usdc_payment" says "payment": a word that usually means money moves, which cannot be taken back.
What this check looks for

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.

All changes to this server

Install

Pinned to version 1.2.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http base-usdc-verifier https://x402-usdc-verify.onrender.com/mcp

claude mcp add --transport http base-usdc-verifier https://x402-usdc-verify.onrender.com/mcp

Run 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.

.claude/settings.json

{
  "permissions": {
    "allow": [
      "mcp__base-usdc-verifier__get_pricing"
    ],
    "ask": [
      "mcp__base-usdc-verifier__verify_usdc_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 base-usdc-verifier. Review it before you use it.

Capability tags behind 1 rule

mcp__base-usdc-verifier__verify_usdc_payment untrusted-input

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/com.onrender.x402-usdc-verify/base-usdc-verifier/verify?hash=e8062d6e22831d3706e2aa7dd13c5c84e1531cd9de4b34d50788a545b424fcf1" | jq -e '.changed == false'

Pinned hash e8062d6e2283, from Oct 28, 2026, 13:17 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/com.onrender.x402-usdc-verify/base-usdc-verifier/changes.xml

An Atom feed. Works in any feed reader or Slack's RSS app.

Badge

[![anlyon.dev](https://anlyon.dev/badge/com.onrender.x402-usdc-verify/base-usdc-verifier.svg)](https://anlyon.dev/servers/com.onrender.x402-usdc-verify/base-usdc-verifier)

Source: MCP Registry. Synced Oct 28, 2026, 13:17 UTC.