recon_subdomains

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

With no annotations, the description must fully disclose behavioral traits. It states the tool is 'passive' and uses Certificate Transparency logs, which implies a read-only, non-intrusive operation. However, it does not explicitly mention rate limits, authentication needs, or any side effects, leaving some ambiguity for a tool with no annotation coverage.

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, well-structured sentence that front-loads the action ('Passively enumerate') and provides the source ('Certificate Transparency logs') without any redundant or extraneous information.

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 simple one-parameter tool and the presence of an output schema, the description sufficiently covers the core purpose and source. It notes the passive nature and CT log source, but could enhance completeness by mentioning its relationship to active DNS enumeration tools or its coverage limits.

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 only defines a 'domain' string with no description. The description compensates by explaining that the tool enumerates sub-domains of 'a domain,' making it clear that the parameter is the target domain. This adds meaningful semantics beyond the raw schema.

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's function: 'Passively enumerate sub-domains of a domain from Certificate Transparency logs.' It uses a specific verb (enumerate) with a resource (sub-domains) and distinguishes itself from sibling tools like dns_lookup and port_scan by specifying the passive CT log source.

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 provides no explicit guidance on when to use this tool versus alternatives. It does not mention any exclusions or recommended use cases beyond its basic function, leaving the agent to infer the appropriate context from the passive nature and source.

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