Skip to main content
Glama
Sign In

cra-check

by io.github.holistis
OverviewDiscussionsAdmin

Check a public x402 payment endpoint before paying it

check_x402_endpoint
Read-onlyIdempotent

Makes one anonymous request to a public x402 payment endpoint, without ever paying, and reports whether its payment request passes the official buyer schema and how far up the receipt ladder the seller gets (does it name what it sells, does it sign its offer, does it return a signed receipt). Use it before an agent pays an endpoint it has not used before. The answer carries verdicts only, never the endpoint's raw headers or body. It is an indication from one request, not an endorsement, not a security review and not a promise that the seller will deliver; every answer says what it did not measure.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "url": "<url>"
    },
    "name": "check_x402_endpoint"
  }
}

Input Schema

NameRequiredDescriptionDefault
urlYesThe https address of the paid route to check
methodNoThe method the route is paid with; POST when not given

Schema Changelog

Changes observed during successful MCP inspections.

  1. Added

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, non-destructive, and open-world, so the bar is lower; the description still adds real context: exactly one request, anonymous, no payment ever made, and output limited to verdicts with no raw headers or body. The remaining gap is that it does not say what happens on network failure or non-x402 responses, which matters for an open-world probe.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The capability and the trigger are front-loaded before the disclaimers, and each sentence carries distinct information. The closing disclaimer clause is somewhat repetitive in listing three negations, but it serves a real purpose in bounding interpretation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description must convey the return shape, and it does at a high level: verdicts about buyer-schema conformance and receipt-ladder rungs, plus an explicit note that every answer lists what it did not measure. A brief indication of the response's structure (fields or shape) would close the last gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters (url, method) are documented with types, an enum, and length bounds. The description adds no parameter-level detail such as URL format constraints or when to override the POST default, so it sits at the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence names a specific verb ('Makes one anonymous request'), the exact resource ('a public x402 payment endpoint'), and the explicit non-action ('without ever paying'), then enumerates what it reports (buyer-schema validity, receipt-ladder progress). Nothing about it could be confused with the sibling check_github_repo.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states the triggering condition directly: 'Use it before an agent pays an endpoint it has not used before.' It also supplies scope exclusions — not an endorsement, not a security review, not a delivery promise — so the agent knows what conclusions the result does not license.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All cra-check toolsInspect
Try in Browser
One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources