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

With no annotations provided, the description carries full behavioral disclosure. It does reveal return contents (specific fields, raw JSON) and auto-detection behavior. However, it omits potential errors, rate limits, or external lookup implications, leaving some gaps in transparency.

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?

Two well-structured sentences: the first identifies the action and inputs, the second enumerates outputs. Every word adds value, with no repetition or filler.

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?

Given the tool's complexity (multi-type queries, no output schema), the description lists a comprehensive set of return fields and input types. It lacks explicit error/edge-case handling, but for a standard lookup tool, the provided context is largely sufficient.

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 100% description coverage with examples. The description adds beyond-schema meaning by explaining that query type is auto-detected, reducing ambiguity about how to format the 'query' parameter for IPs, ASNs, or domains.

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 ('look up') and resource ('registration data via RDAP'), and clearly enumerates accepted input types (IP, ASN, domain). This distinguishes it from sibling DNS/SSL/uptime tools, which focus on different concerns.

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 explicitly lists valid query types and notes automatic detection, making it clear when this tool is appropriate. It does not explicitly name alternative tools or exclusion cases, but the scope is well-defined enough for an agent to select it for registration/ownership lookups.

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