list_verified_sites

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 agent knows this is a safe, read-only operation. The description adds the behavioral nuance that verified domains are not automatically Search Console properties, which helps interpret results. However, it doesn't disclose details like data freshness or whether the list includes subdomains, but the annotations carry the main burden.

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?

Three sentences, each earning its place: the first states scope, the second clarifies the distinction from a sibling, and the third explains the practical use case. No fluff, front-loaded with the core purpose.

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 required parameters and no output schema, the description is sufficient. It explains why this tool exists, when to use it, and how it differs from a sibling. The only minor gap is not describing the format of the returned list, but that is not critical given the annotations and simplicity.

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 single parameter 'account' is fully documented in the schema with description and instruction to call list_accounts. The description provides no additional parameter semantics, but schema coverage is 100%, so the baseline of 3 is appropriate.

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 ('list') and resource ('every site and domain this Google account has verified ownership of, across all Google products'), and explicitly differentiates from list_sites. It clearly conveys the scope and purpose, distinguishing it from the sibling tool.

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 explicitly contrasts with list_sites and explains when to use this tool: to distinguish 'not verified yet' from 'verified but never added'. It also implies when to use the alternative (list_sites for Search Console properties). This provides clear usage context and exclusions.

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