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

With no annotations present, the description carries the burden well: it discloses the price and currency, accepted chains (Base or Solana), that no account or API key is needed, and that failed calls are not charged — the last being a genuinely useful billing-behavior detail. It stops short of rate limits, timeout behavior, or how payment is actually settled per call.

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?

Front-loaded and dense: what it does, what it returns, what it costs, what auth it needs, and the endpoint, in five short fragments with no filler. The telegraphic style costs a little readability but nothing is wasted.

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 tool with no annotations and no output schema, the description covers cost, payment rails, auth requirements, failure billing, and the fields returned — enough to call it correctly and predict the response shape. Only rate limits and response/settlement mechanics are unaddressed.

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% for the single `domain` parameter, so the schema already documents it. The description only restates "for a domain" and adds no format, normalization, or subdomain-handling detail beyond the schema's own example.

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?

Specific verb and resource: "SSL/TLS certificate check for a domain", followed by the exact data points returned (validity, issuer, expiry, days left, TLS version, SANs). This lets an agent separate it from sibling domain tools like buy_domain_whois or buy_domain_dns without opening any schema.

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 paid framing ("Paid.", "$0.02 USDC") implicitly signals this is for use when a cert check is worth paying for, but the description never names an alternative or states when-not to use it relative to the other domain/website tools in the sibling list. Guidance is implied by the resource, not stated.

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