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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds valuable behavioral context: that verified domains yield faster checks, and that verification is interactive and performed outside the API. This goes beyond annotations without contradicting them, providing useful operational insight.

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?

The description is three sentences, each with a distinct purpose: the main function, the performance benefit, and the verification method. It is front-loaded with the core action and contains no filler or redundant phrasing.

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 list tool with no parameters and no output schema, the description covers all necessary aspects: what it lists, why it matters, and how verification works. An agent would know exactly what to expect and when to use it. No critical information is missing.

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?

The tool has zero parameters, so the schema fully covers them (100% coverage). The description adds no parameter-specific details because none are needed. Per the baseline for zero parameters, a score of 4 is appropriate; there is nothing to compensate for.

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 states a specific verb ('Lists') and resource ('the domains this account has proven ownership of'), clearly distinguishing it from siblings like get_job_results or submit_urls which deal with jobs and URL submissions. The scope is unambiguous and immediately understandable.

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?

The description explains when this tool is relevant: to retrieve verified domains for faster checks, implying usage before operations that benefit from verified status. It also clarifies that verification itself is not done through this API but via the web dashboard, setting expectations. While it doesn't name alternative tools explicitly, the context makes its purpose distinct from siblings.

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