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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false), so the bar is lower; the description still adds genuine behavioral context by disclosing the two verification mechanisms and their prerequisites. It does not state what happens on success/failure or whether a previously verified domain can be re-verified, which keeps it short of a 5.

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?

A single sentence with the core action front-loaded and no filler; the trailing DNS/well-known clause is dense but informative. It is slightly run-on but every clause earns its place.

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 mutation tool with no output schema and a 25%-covered 4-parameter schema, the description covers the verification flow but leaves the identity parameters (reference, listing_token) and the outcome of a successful verification unspecified. Adequate but with clear gaps.

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?

Schema description coverage is only 25% — only email_code is documented. The description usefully clarifies that email_code is optional depending on the verification path, but reference, listing_token, and schema_version are unexplained in both schema and description, leaving three of four parameters opaque.

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+resource: 'Prove control of the company domain for a listing request', which is distinct from sibling tools like request_listing, approve_listing, or get_listing_status. It doesn't explicitly name a sibling to route against, but the domain-verification action is unambiguous on its own.

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 clearly states the two invocation conditions: pass email_code with the received code, or call without it once the DNS TXT record or /.well-known/aci-verification.txt file is in place. That is real when-to-use guidance, though it offers no exclusions or comparison to alternatives.

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