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

Annotations already declare readOnlyHint=true/destructiveHint=false, and the description adds genuinely non-redundant behavior: no payment triggered, no contract concluded, the link is not a pre-filled cart link and the customer must re-select the domain. This discloses side-effect boundaries and the checkout flow that annotations cannot express, and it is consistent with the read-only annotation.

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?

The key capability (WHOIS check + price + link) is front-loaded, and the disclaimers are placed after it. It is on the verbose side, with the parenthetical legal aside '(rechtlich bewusst kein automatischer Kauf per Chat)' being somewhat expendable, but each sentence still carries meaning.

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 compensates by naming the return contents (price and pre-filled search link) and the failure case (no link when taken). For a one-parameter tool with annotations covering safety, nothing an agent needs to invoke 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 description coverage is 100%, and the single 'domain' parameter already documents itself with an example (example.de). The description adds no format, TLD, or validation detail beyond the schema, so the baseline 3 for schema-does-the-work 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 and resource (prüft eine Domain per WHOIS) and names the concrete outputs (Preis, Link zur vorbelegten Domainsuche). It also names the sibling suggest_domain_alternatives, so an agent can distinguish this tool from check_domain_availability and prepare_hosting_order without opening a 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?

Explicit about the fallback case: 'Ist die Domain vergeben … dann suggest_domain_alternatives nutzen', which is true when-to-use guidance with a named alternative. It also warns this is not a cart link, but it doesn't clarify when to prefer this over check_domain_availability or prepare_hosting_order, so it stops short of explicit when-not coverage.

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