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

Annotations already provide readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context by revealing that the tool queries the certificate provider externally and may transition the domain into a serving state. This goes beyond what the annotations express and does not contradict them.

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 a single, well-structured sentence that front-loads the core action and then adds the conditional behavior. There is no filler or redundant information.

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, idempotent tool with safety annotations, the description covers the essential behavior and the condition under which a side effect occurs. It does not document output shape or error handling, but given the tool's simplicity and the absent output schema, this is only a minor gap.

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?

The schema already provides a clear description for the only parameter, 'domain', including the important qualifier 'exactly as it was connected.' The description adds no additional parameter-level detail, but since schema coverage is 100%, the baseline of 3 is appropriate.

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 clearly states the tool's specific action: querying a certificate provider about a pending custom domain and conditionally beginning to serve it. It is distinct from sibling tools like list_domains or add_domain, so an agent can correctly identify when to invoke it.

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 conveys a clear usage context: use it when a custom domain is pending and you need to know its status, with the added behavior of serving it if ready. It does not explicitly name alternative tools or exclusions, but the situation is unambiguous enough for an agent to select it appropriately.

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