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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so 'Changes nothing by itself' largely restates them. The description does add useful behavioral context: the token form varies (meta tag for URL-prefix sites, DNS TXT for Domain properties) and tells where it must be placed.

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 dense sentence, front-loaded with the verb+resource, followed by the variant detail. No filler.

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 single-param read-only tool with no output schema, the description covers what the token is, its two forms, and where it goes. It stops short of describing how the caller should use the returned token, which is minor given no output schema is defined.

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?

One required parameter with 0% schema description coverage. The description partly compensates by distinguishing URL-prefix sites from Domain properties, which implicitly signals two valid site_url shapes, but it never explains the accepted URL format or whether the bare domain is required for Domain properties.

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 ('Get the ownership-verification token for a client's site') and distinguishes itself from the sibling site_verify by scoping to token retrieval rather than performing verification.

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 — an agent can infer this is a prerequisite step before site_verify — but the description never states when to call it versus site_verify or what precedes/follows it. No explicit when/when-not guidance.

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