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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds real context beyond them: 'This call asks no human' tells the agent there is no confirmation gate, and it previews the response payload (status, reason, remaining DNS records), which matters since no output schema exists.

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?

Two compact clauses with the action front-loaded and the non-interactive guarantee placed last where it is most actionable. The phrase 'and why' is slightly cryptic about what question is being answered, a minor cost to an otherwise efficient sentence.

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?

Adequate for a read-only 3-param tool with no output schema: it tells the agent what comes back and that no human approval is needed. It leaves the project/environment scoping and any domain-not-found or auth failure behavior unaddressed, which is a noticeable gap given two undocumented parameters.

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 33%: 'domain' is documented in the schema, but 'project' and 'environment' have no description anywhere, only a regex pattern. The description says nothing about how those two scoping parameters interact with the hostname, so it fails to compensate for the coverage gap.

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 ('Check') and resource ('domain') and enumerates what the check returns: status, reason, and pending DNS records. That is enough to separate it from the mutating siblings domain_add/domain_update/domain_remove, though no sibling is named explicitly.

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?

'Check a domain now' implies an on-demand verification, most plausibly after adding or updating a domain, but the description never states when to reach for it versus domain_add or domain_update, nor any prerequisite (e.g. the domain must already exist). Usage is only implied.

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