check_domain_availability

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 adds valuable context beyond basic functionality by specifying the methods used ('DNS, RDAP, and WHOIS lookups') and the return information ('availability status and details'). However, it lacks details on rate limits, error handling, or authentication needs, which would be beneficial for a tool performing external lookups.

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 appropriately sized and front-loaded, consisting of two concise sentences that directly state the tool's purpose, methods, and return values without any redundant information. Every sentence earns its place by providing essential details efficiently.

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 moderate complexity (single parameter, no output schema, no annotations), the description is fairly complete. It covers the purpose, methods, and return information adequately. However, without an output schema, it could benefit from more details on the structure of 'availability status and details' to fully guide the agent, but it provides enough context for basic 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 input schema has 100% description coverage, with the single parameter 'domain' clearly documented in the schema. The description does not add any additional meaning or syntax details beyond what the schema provides, such as format examples or validation rules. Given the high schema coverage, the baseline score of 3 is appropriate as the schema handles the parameter documentation effectively.

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 clearly states the specific action ('Check if a domain name is available for registration'), identifies the resource ('domain name'), and distinguishes it from its sibling 'check_multiple_domains' by implying this tool handles single domains. The verb 'check' and resource 'domain name' are precise and unambiguous.

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 implies usage context through 'Check if a domain name is available for registration,' suggesting this tool is for availability verification. However, it does not explicitly state when to use this versus the sibling 'check_multiple_domains' or provide any exclusions or prerequisites. The guidance is implied but not detailed.

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