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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive, but the description adds a critical non-obvious behavior: it consumes Potarix Enricher API credits. This cost side effect is not captured by annotations and is essential for an agent to know before invocation. It does not mention rate limits or return shape, but the annotation coverage reduces the need for those details.

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 exactly two sentences: the first states the purpose, and the second states the cost implication. It is front-loaded, actionable, and contains zero filler 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 tool with only one string parameter, complete schema coverage, and strong annotations, the description is adequately complete. It specifies the input domain, the purpose, and the credit cost. The lack of explicit return format or sibling differentiation is a minor gap, but the low complexity and available annotations make this sufficiently informative for correct use.

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 schema already provides 100% description coverage for the single `domain` parameter, including an example ('stripe.com'). The tool description merely restates 'for a domain' and adds no additional meaning beyond what the schema provides, so the baseline score of 3 applies.

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 uses a specific verb and resource: 'Find public company email contacts for a domain.' This clearly distinguishes it from sibling tools like find_person_email and find_decision_maker_email, which target individual contacts rather than general company contacts.

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 does not provide any guidance on when to use this tool versus the sibling alternatives. It does not mention that find_person_email is for individual people or that find_decision_maker_email is for leadership contacts, leaving the agent to infer the scope from the tool name alone.

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