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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds the specific scope (ownership, DNS linkage, conflicts) and restates no mapping/DNS record changes, but it does not describe return format or error behavior.

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 sentences, front-loaded with the main action and domain scope, followed by the key no-side-effect guarantee. No wasted words.

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 2-parameter read-only preflight with rich annotations, the description covers what is checked and the no-change guarantee. It lacks output shape details since there is no output schema, but the described data categories give adequate context.

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?

With 0% schema description coverage, the description must compensate, and it does clarify domain types (.ton, .t.me, supported subdomain) and that site is an owned site. However, it does not specify exact identifier formats for site or domain beyond that.

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?

Description states a specific read-only purpose: checking ownership, DNS linkage, and conflicts for supported domain types before attaching. It clearly differentiates from siblings like sites.attach_domain and sites.unlink_domain by emphasizing no changes are made.

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?

It explicitly frames usage as a preflight step before attaching a domain, and the final sentence clarifies it is not for making mapping/DNS changes. It does not explicitly name alternative tools for regular DNS lookups, but the before-attaching context is clear.

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