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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false. The description adds real behavioral context the annotations lack: the return fields verifiedAt/validUntil and the 24-hour validity window. It does not say what happens on a failed or repeated verification, so it falls short of a 5.

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?

Five short sentences, front-loaded with the operation, then prerequisites, then outcome and the authorization disclaimer. Every sentence carries distinct information; nothing is redundant with the schema or annotations.

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?

With no output schema, the description usefully names verifiedAt and validUntil and the validity duration, and it states the prerequisite sequence and non-authorization boundary. It omits failure modes (e.g., what a TXT mismatch returns), which is the only remaining gap for a verification tool.

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%, and both secret and clientId are thoroughly documented there, including the Authorization-header alternative. The description mentions authentication only obliquely ('currently authenticated agent') and adds no parameter detail, so the baseline 3 applies.

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 states a specific verb and resource: 'Check the DNS TXT challenge ... and record domain-control verification' for the currently authenticated agent. It is clearly distinguishable from the sibling kya_challenge, which it names as the prerequisite step.

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?

It gives explicit prerequisites (OAuth scope commerce.order, and 'First call kya_challenge and publish its exact DNS TXT record') and an explicit boundary ('This does not authorize a purchase or a payment'). An agent knows the ordering and the scope of the operation without inference.

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