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

Annotations declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, but the description adds substantial context beyond them: no payment is triggered, no contract is concluded, it is not a ready-made cart link, and the customer must re-search. This is exactly the behavioral detail an agent needs.

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 with the core action and return, followed by clarifying caveats. It is somewhat long, but each sentence adds a distinct legal/behavioral nuance rather than repeating structured data.

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 exists, yet the description explains return values (price and link, or no link), the no-payment/no-contract boundary, and the fallback tool. Complete for a read-only WHOIS check.

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% with a single documented parameter (example format given), so the schema already carries the semantics. The description adds no syntax or format detail beyond what the schema provides, 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: checks a domain via WHOIS and returns price plus a pre-filled search link. It also distinguishes itself from check_domain_availability and suggest_domain_alternatives by describing exactly what it produces and what it is not.

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?

Explicitly routes the agent: when the domain is taken, use suggest_domain_alternatives instead. It also clarifies when this is the right tool (preparing an order link) versus a full cart/checkout flow.

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