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

The description adds substantial behavioral detail beyond the annotations: it states the maximum number of generated names, the mutation methods, that DNS name servers are checked live, how registered-looking names are reported, and that a lack of name servers does not imply the domain is unregistered. It also discloses pricing, payment rails, and that failed calls are not charged.

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 front-loaded with the core behavior, then adds interpretive caveats and pricing in a compact sequence. Every sentence carries useful information, and no space is wasted on restating the tool name or schema.

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?

With an output schema present, the description does not need to document return structure in detail, and it still explains the key output form (registered-looking names with name servers). It also covers the important caveats and payment model, leaving no obvious gap for correct invocation or interpretation.

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 coverage is 100% and the single parameter is already documented in the schema with an example format. The description reinforces that the input is a brand domain but does not add syntax, constraints, or normalization rules beyond what the schema provides.

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 and resource: generates lookalike domain names for a brand domain and checks their DNS name servers. It explicitly scopes the output to registered-looking names and lists the mutation techniques, so an agent can immediately tell what the tool does and how it differs from general DNS or reputation tools.

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?

Usage is implied by the opening phrase 'For a brand domain' and the typosquatting context, but the description does not explicitly state when to use this tool versus alternatives such as WHOIS/RDAP or phishing checks. It does include a useful caveat that the result is not a trademark or phishing verdict, which helps interpretation but is not the same as usage routing.

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