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

With no annotations, the description carries the full burden, and it usefully discloses that it performs a live SMTP check and catch-all detection — which signals latency, possible greylisting/failure, and reduced reliability for catch-all domains. It omits what happens when no email is found, whether results are cached, and any rate-limit or auth expectations, so it is partial rather than complete.

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 tight sentence with the resource front-loaded and the operational detail (live SMTP check, catch-all detection) parenthetically appended. Zero 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 3-param tool with no output schema and no annotations, the description covers the input contract and one operational trait but says nothing about the return shape (email only? confidence score? null on failure?) or failure modes. An agent can invoke it, but cannot anticipate the response.

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 0%, so the description must compensate; it merely restates the three field meanings (first name, last name, company domain) already obvious from the param names. It never specifies the domain format (bare 'example.com' vs URL) nor notes that last_name is optional while first_name and domain are required, leaving real format ambiguity unresolved.

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 and resource ('Find a person's verified work email') plus the distinguishing output trait (verified). It doesn't mention the siblings verify_email or domain_email_intel, so an agent must infer why this differs from plain verification, but the core purpose is unambiguous.

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 implies the required inputs but never says when to choose this over verify_email or domain_email_intel, nor any prerequisite or exclusion. No usage guidance beyond the implicit 'you have a name and domain' condition.

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