Point it at any URL that claims to sell over x402 and get a conformance verdict: does it actually return a 402, is the challenge valid v2 JSON, are the payment requirements complete, is the price above the CDP settlement floor, and does the PAYMENT-REQUIRED header match the body. $0.02/call via x402.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | The https URL of the x402 endpoint to verify | |
| method | No | HTTP method the endpoint sells on | GET |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It goes beyond a simple 'verify' by disclosing specific behavioral aspects: it performs live checks (whether the URL returns a 402, validates v2 JSON, etc.) and the cost of $0.02 per call. It doesn't mention response format or side effects, but still provides substantial behavior context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is exactly two sentences. The first front-loads the purpose, and the second lists the checks and cost. No redundancy or filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description covers the core behavior and checks thoroughly. However, there is no output schema, and the description does not specify the exact return format of the 'conformance verdict' or handle error cases (e.g., unreachable URL). This is a minor gap for a tool with such a clear purpose.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, with both 'url' and 'method' having descriptions. The tool description does not add meaning beyond the schema; it only frames the URL as an x402-selling endpoint. This meets the baseline of 3.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states a specific verb ('get a conformance verdict'), a resource (any URL that claims to sell over x402), and enumerates the exact checks performed. This distinguishes it from sibling tools like settlement_verify, which likely verifies settlements, and x402_receipt_lookup, which looks up receipts.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives a clear trigger condition: use this when you encounter a URL that claims to be an x402 endpoint. It doesn't explicitly mention alternatives or exclusions, but the use case is well implied, making it clear when to invoke this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.