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

Goes well beyond the annotations (readOnly=false, destructive=false, openWorld=false): it discloses the ownership prerequisite, non-reset extension semantics, the two-step x402 handshake with the exact _meta['x402/payment'] key, the PaymentRequired price discovery call, the receipt location, and that no account/API key is needed.

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?

Purpose and payment flow are front-loaded and efficient. However, the trailing three-sentence /feedback block about complaints and quote requests does not help an agent select or invoke this tool, so it dilutes an otherwise tight description.

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?

No output schema, yet the description states what is returned (new and previous expiry) and fully describes the payment protocol an agent must execute. Nothing needed to call it correctly is missing.

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 coverage is 100% and the single 'name' parameter is fully documented in the schema. The description adds only the ownership constraint on the payer, not additional syntax or format detail, so 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?

States a specific verb+resource with precise scope: 'push a name you own further out by another year.' It also clarifies the effect ('only its expiry moves'), which distinguishes it from dns_rent and from dns_set_records without naming them.

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?

Gives clear context: it applies only to names you already own, the payer must be the owner, and repeated payment extends rather than resets. It does not explicitly name sibling alternatives (e.g. dns_rent for new rentals), so routing is inferred rather than spelled out.

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