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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'no key', implying no authentication is required, but it does not disclose rate limits, output format, error handling, or any other behavioral traits. An agent has no idea what to expect when calling this tool.

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 extremely short, which is concise, but it is a fragment rather than a structured sentence. It lacks essential information and does not front-load the most critical details (what the tool does, what input it expects). The brevity is not beneficial because it omits necessary context.

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?

The tool has one parameter, no annotations, and an output schema (though not shown). The description is incomplete: it does not state the tool's purpose clearly, does not explain the parameter, and provides no usage context. For a simple tool, this is still insufficient for an agent to use it correctly.

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 has a single parameter 'q' with 0% description coverage. The description does not explain what 'q' represents (likely a domain name or IP address) or provide any formatting guidance. Since the schema provides no description, the tool description must compensate, but it fails to do so entirely.

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 'RDAP Registration: Structured domain registration record (RDAP/IANA bootstrap, no key)' is vague. It implies the tool deals with RDAP and domain registration records, but it is unclear whether it performs a lookup or a registration. It does not specify the action (e.g., 'query' or 'fetch') and does not distinguish it from similar siblings like 'rdap_domain' or 'whois'. The term 'Registration' could mislead an agent into thinking it registers domains, which is likely incorrect.

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?

There is no guidance on when to use this tool versus alternatives. With many RDAP-related siblings (e.g., 'rdap_domain', 'rdapip') and 'whois', the description does not mention any selection criteria. The only hint is 'no key', which suggests it requires no authentication, but it does not explain why one would choose RDAP over whois or other domain lookup tools.

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