Subdomain discovery

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

Despite no annotations, the description discloses the methods (CT logs, common-prefix probing) and that DNS resolution status is included. It does not mention rate limits, data freshness, or potential limitations, but the provided information is fairly transparent for a discovery 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 a single, front-loaded sentence that efficiently conveys the tool's purpose, methods, and output. Every word earns its place with no redundancy.

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 no output schema, the description provides a vague idea of the return (subdomains with DNS resolution status) but lacks specifics on the output structure or fields. For a simple tool with one parameter, it is adequate but could be more complete by detailing the format or whether it returns a list or map.

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 single parameter 'domain' is fully described in the schema (100% coverage). The description adds value by explicitly noting that protocol, www, and paths are stripped automatically, which aids the agent in formatting input correctly.

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 tool discovers subdomains using Certificate Transparency logs and common-prefix probing, with DNS resolution status. It distinguishes itself from siblings like dns_records or domain_reputation by focusing on subdomain enumeration specifically.

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?

No explicit guidance on when to use this tool versus siblings. The description only explains what it does, not the context or alternatives. Usage is implied by the name and description, but no when-not-to or comparisons are provided.

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