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

No annotations provided, but description discloses pricing ($0.02 per call), payment method (x402), no account needed, and specific data returned. Does not mention limitations or destructive behavior.

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?

Description is informative but slightly verbose. Front-loaded with purpose and pricing. Each sentence adds value, though could be more concise.

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 single-parameter tool, description covers input usage, output types, and pricing. Output schema missing, but explanation of returned records compensates. Adequately complete.

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 has 100% coverage with description for 'domain'. Main description adds example and context but does not significantly extend schema's meaning. Baseline 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?

Clearly states it provides DNS and email intelligence for a domain, listing specific record types and email provider detection. Distinct from sibling tools like whois or assess.

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?

Explicitly says 'Give it a domain' and mentions use cases like deliverability checks and lead qualifying. Lacks explicit when-not-to-use but is clear enough.

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