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paidfor

dev.paidfor/paidforpaidfor.devstreamable-httpv0.4.0Scanned

Check an x402 seller before paying: verdict, failure rate and evidence from paid calls on Base.

4 tools: 1 do something that can't be undone and 3 change things.

Tools: 0 delete, 1 irreversible, 3 write, 0 read.
  • Reads private data · 0
  • Reads text others write · 4
  • Can send data out · 2
  • 3 findings

Anlyon alternative

4 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.

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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.

4 tools

Can't be undone 1Claude Code: ask
  • report_x402_paymentAfter your agent pays an x402 seller with any wallet, report what came back.Reads text others writeCan send data outNo findings

    Why it is in this group

    • The name "report_x402_payment" says "payment": a word that usually means money moves, which cannot be taken back.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    • outboundThe input takes a URL (input.url): a request to a URL can carry data to whoever runs it.
    Description, as the server wrote it
    After your agent pays an x402 seller with any wallet, report what came back. Needs the resource URL, the settlement transaction hash and the outcome. Free, no account, no key; the report counts only with on-chain proof.

    Annotations the server declares

    • readOnlyHint: false
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • title: Report an x402 payment outcome
Changes things 3Claude Code: ask
  • check_x402_sellerCall this before any x402 payment, before retrying a request that answered HTTP 402, or whenever the user is about to buy an API call with USDC on Base or names an API they intend …Reads text others writeCan send data out1 finding

    Why it is in this group

    • The description's first verb is "call": a word for a change.
    • 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.
    • outboundThe input takes a URL (input.url): a request to a URL can carry data to whoever runs it.

    Findings

    • Warn

      The server marks "check_x402_seller" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Call this before any x402 payment, before retrying a request that answered HTTP 402, or whenever the user is about to buy an API call with USDC on Base or names an API they intend to pay per call. Returns a verdict (avoid, caution, ok, unknown), one sentence to act on, the seller's paid-call count and failure rate with a 95% interval, listed price, modal quote and max overcharge ratio when known, and links to the seller page and raw evidence.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • title: Check an x402 seller before paying
  • list_reliable_sellersCall this when choosing among sellers for a task, or when the user asks for a safe or reliable API.Reads text others write1 finding

    Why it is in this group

    • The name "list_reliable_sellers" says "list": a word for reading.
    • The description's first verb is "call": a word for a change.
    • 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 "list_reliable_sellers" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The name "list_reliable_sellers" says "list": a word for reading.

      What this check looks for
    Description, as the server wrote it
    Call this when choosing among sellers for a task, or when the user asks for a safe or reliable API. Returns sellers with zero failures across at least 30 paid calls, most-called first. For each: domain, category, paid-call count, the 95% upper bound on its failure rate, median quoted price in USDC, USDC paid to it in the last 30 days, when it was last seen, and its paidfor seller page.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • title: List reliable pay-per-call API sellers
  • recent_changesCall this when the user asks what changed, or before relying on a verdict older than a day.Reads text others write1 finding

    Why it is in this group

    • The description's first verb is "call": a word for a change.
    • 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 "recent_changes" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Call this when the user asks what changed, or before relying on a verdict older than a day. Returns recent changes, newest first: verdict changes, new failures by type, moved quotes, changed pay-to addresses, sellers added or reaching 30 paid calls, published seller replies, the operator-reported series maturing or disagreeing with ours. Each change has its time, type, seller domain, seller page and type-specific details (for example the old and new quote).

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • title: Recent changes to x402 sellers

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.

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 out2
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.

3 warn
  • Warncheck_x402_seller

    The server marks "check_x402_seller" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

    What this check looks for
  • Warnlist_reliable_sellers

    The server marks "list_reliable_sellers" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The name "list_reliable_sellers" says "list": a word for reading.

    What this check looks for
  • Warnrecent_changes

    The server marks "recent_changes" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "call": a word for a change.

    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 0.4.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http paidfor https://mcp.paidfor.dev/mcp
claude mcp add --transport http paidfor https://mcp.paidfor.dev/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": [],
    "ask": [
      "mcp__paidfor__check_x402_seller",
      "mcp__paidfor__list_reliable_sellers",
      "mcp__paidfor__recent_changes",
      "mcp__paidfor__report_x402_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 paidfor. Review it before you use it.

Capability tags behind 4 rules
  • mcp__paidfor__check_x402_seller untrusted-input, outbound
  • mcp__paidfor__list_reliable_sellers untrusted-input
  • mcp__paidfor__recent_changes untrusted-input
  • mcp__paidfor__report_x402_payment untrusted-input, outbound

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/dev.paidfor/paidfor/verify?hash=f44c109a3408542acb19a779d1915d672113b9a53f42de8f786a749c135127b4" | jq -e '.changed == false'

Pinned hash f44c109a3408, from Oct 30, 2026, 03:18 UTC.

Watch

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

https://anlyon.dev/servers/dev.paidfor/paidfor/changes.xml

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Source: MCP Registry · repository. Synced Oct 30, 2026, 03:17 UTC.