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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does so thoroughly. It discloses the financial side effect ('deducts from account balance'), the asynchronous DNS zone initialization behavior, and the two-stage confirmation flow ('returns an actionId... call executeConfirmedAction'). It even warns about the race condition with createDnsRecord and how to handle it.

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 description is dense but well-organized: purpose and side effect first, then DNS-related caveats, then required/optional parameters, then the return-and-confirm flow. Every sentence adds distinct information and none of it duplicates the schema. It is appropriately front-loaded for an agent scanning for purpose and critical warnings.

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 tool with eight parameters, a nested object, no output schema, and no annotations, the description covers the essential operational context: required vs optional fields, examples, the financial impact, asynchronous DNS behavior, retry guidance, and the actionId confirmation handoff to executeConfirmedAction. This is enough for an agent to invoke the tool correctly and follow through on the post-call workflow.

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 only ％13%, so the description must compensate, and it substantially does: it identifies required vs optional parameters, gives concrete examples for domain and nameservers, constrains years to 1-10, and clarifies the default for initializeDnsZone. The only gap is that the nested registrantInfo object is summarized as 'contact details' without elaborating its required subfields or format, and sessionKey is not mentioned here — though the schema itself fully documents sessionKey.

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?

The description opens with the specific verb 'register' and the resource 'domain name', and clearly frames this as a registration action, not renewal or transfer. It also distinguishes the tool from the nearby initializeDnsZone and createDnsRecord siblings by explaining that DNS zone initialization is handled automatically. The staging/confirmation nature is explicit, so an agent can select it correctly.

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 description gives concrete when-to-use guidance: use this for new domain registration, and there is no separate initializeDnsZone call needed. It also instructs the agent to retry createDnsRecord after a delay if the zone is not yet visible, and to call executeConfirmedAction with the returned actionId after user approval. This provides a clear operational path and names the relevant sibling tool.

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