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

Annotations already disclose openWorldHint=true (external DNS lookups), destructiveHint=false, and notably readOnlyHint=false. The description adds that it re-checks ('again') and reports missing records, which is useful. It does not explain why a 'check' is marked non-read-only (e.g., it triggers re-verification) nor any rate limits, leaving some tension with the annotation unresolved.

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 tight sentences with the usage trigger front-loaded and the behavior following. No filler, though it could be marginally more economical.

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 simple two-parameter verification tool with an output schema present, the description covers when to use it and what it returns conceptually, so return-format detail is unnecessary. The only real gap is the undocumented site_id and the unaddressed non-read-only annotation.

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 50%: 'domain' is documented in the schema ('Leave out to check them all') but 'site_id' has no schema description, and the description adds no semantics for either. The phrase 'the site's custom domains' implies site_id scoping but does not compensate for the undocumented parameter. Baseline 3.

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 the site's custom domains') and clarifies the return ('each one's status and which records are still missing'). It is distinguishable from connect-domain (setup) and set-site-address, though it never names those siblings 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?

Gives a concrete trigger: 'when the user has set their DNS records, or asks whether their domain works yet.' That clearly situates it in the domain-verification flow. It stops short of naming the alternative tools an agent might pick instead.

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