dns_reverse

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

With no annotations, the description takes on full responsibility for behavior disclosure. It transparently describes the two-step process: resolving the PTR record and then forward-resolving the hostname to confirm mapping. It doesn't mention edge cases like missing PTR records, but the core behavior is well disclosed.

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 two sentences: the first states the core purpose and the second elaborates the validation flow. Every word is necessary, and it's front-loaded with a clear verb.

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 one-parameter DNS tool, this description is complete: it explains both the lookup and the validation logic. There is no output schema, but the behavior is sufficiently described to understand what the tool does, though missing potential response details.

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 input schema already provides a clear description for the single 'ip' parameter, and the tool description doesn't add additional parameter details. Since schema coverage is 100%, 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 uses a specific verb ('Perform PTR lookup') with a specific resource ('IP address') and adds the distinctive validation step ('FCrDNS validation'). This clearly differentiates it from sibling tools like dns_lookup or email_check_ptr.

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 clearly implies when to use this tool (when you need reverse DNS with forward-confirmed validation), giving context for its use case. However, it doesn't explicitly name alternatives or exclusions, so it falls short of a 5.

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