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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral fact — '(if any)' signals the result may be empty when no custom domain is configured — plus that DNS status is part of the payload. It does not discuss errors for nonexistent sites or the meaning of DNS status values.

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?

One front-loaded sentence with zero filler; the primary purpose and the nullable-result caveat are both conveyed compactly.

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 single-parameter read tool with full annotations and an output schema, the description covers what the tool returns and flags the empty case, so an agent has enough to call it correctly. Minor remaining gap is the absence of any routing guidance versus sibling get_site_* tools.

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?

There is a single parameter with 100% schema description coverage ('Name of the site'), so the schema carries the parameter burden. The description adds nothing about site_name format or where to obtain it, which is acceptable at this coverage level but earns no bonus.

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 names a specific verb and resource ('Get the custom domain configured for a site') and states what is returned ('its DNS status'), which distinguishes it from generic siblings like get_site_details or get_site_overview. It stops short of explicitly naming those siblings, so an agent must infer the boundary rather than read 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?

Usage is implied — call this when you need the site's custom domain or DNS status — but there is no explicit when-to-use, when-not-to-use, or named alternative. No prerequisites (e.g., site must exist) are stated, leaving the agent to infer routing from the name alone.

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