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

With no annotations, the description carries the full burden, and it does disclose important behavior: $0.01 per call in USDC on Base, paid via x402 in params._meta["x402/payment"], plus the HTTP endpoint. It does not disclose error behavior, whether payment is mandatory before any response, or result shape.

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?

A single dense line with the value proposition front-loaded and pricing/transport tacked on. No filler, though the payment and endpoint details are run together rather than clearly separated.

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 one-parameter lookup with no annotations and no output schema, the description covers what is returned, what it costs, how to pay, and where it lives. Gaps are minor: failure modes and the domain parameter's accepted format (bare hostname vs URL) are unstated.

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 0% and the 'domain' parameter is undocumented in both schema and description. The description does add meaning for an out-of-schema requirement, the x402 payment payload in params._meta, which compensates partially.

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 resource and enumerates exactly what the report contains: DNS, RDAP registration age/expiry/registrar/nameservers, and an email-auth grade. It only implicitly differentiates from siblings like domainkit__dns and domainkit__email via the word 'Full', never 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?

'Full report' implies this is the combined option versus narrower sibling calls, but no explicit when-to-use/when-not or alternative is stated. An agent must infer that domainkit__dns or domainkit__email exist for partial lookups.

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