Full explanation of one rule by id — what it checks, why it matters, how to fix it, and where the rule came from. Use when you want the reasoning without re-probing.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It only describes the tool's function and does not mention whether it is read-only, requires authentication, has side effects, or any performance considerations. The implied read-only nature is not stated explicitly.
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 two sentences: the first explains what the tool does, the second provides usage guidance. It is front-loaded, compact, and contains no unnecessary words.
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?
For a simple one-parameter tool with no output schema, the description covers the purpose and a use-case. However, it lacks parameter format details and does not describe the return structure beyond 'Full explanation'. Given the absence of an output schema, more detail on the response would improve completeness.
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?
The schema description coverage is 0%, so the description must compensate. It adds 'by id' indicating the parameter is an identifier for a rule, but does not explain the format, source, or how to obtain valid IDs. This is minimal added meaning beyond the bare schema.
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 the tool provides a 'Full explanation of one rule by id' and enumerates the content (what it checks, why it matters, how to fix it, where the rule came from). This is a specific verb+resource combination. However, it does not explicitly differentiate from sibling tools like 'list_checks', though the intent is clear enough for an agent.
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 includes 'Use when you want the reasoning without re-probing,' which gives a clear use-case but no explicit when-not-to-use or alternatives. Siblings are not mentioned, so the guidance is implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool has a clearly distinct purpose: probe_x402_endpoint performs the actual endpoint test, list_checks provides the rule table, and explain_defect offers detailed explanations for a specific rule. No overlap or ambiguity.
All tool names follow a consistent verb_noun pattern in snake_case (explain_defect, list_checks, probe_x402_endpoint), making the naming predictable and easy to understand.
With three tools, the server is well-scoped for its purpose: probe to test, list to see all rules, explain to get details on a specific rule. The count is appropriate without being too thin or excessive.
The tool set covers the full workflow for x402 endpoint diagnosis: testing the endpoint, listing all possible checks, and explaining any defect. There are no obvious gaps—the combination of probe, list, and explain is complete for the domain.