Associated domains

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

Annotations already provide readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds value by explaining the association mechanism (shared registrant or infrastructure), which is beyond what annotations say. It does not disclose pagination costs beyond schema, but annotations cover safety profile.

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?

Two sentences with no waste. The first sentence states the core functionality and mechanism; the second gives a clear use case. Efficiently communicates the tool's purpose.

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 simplicity (3 params, all documented), the description is nearly complete. It lacks explicit mention of pagination for large result sets, but the schema documents that. No output schema, but annotation openWorldHint indicates variable results. Could mention how results are ordered or returned, but not critical.

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 includes descriptions for each parameter. The description doesn't add much beyond that, but it implies the domain parameter is the starting point. Baseline 3 applies, but the description's mention of 'shared registrant details or infrastructure' clarifies the intent behind the domain parameter, nudging to 4.

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?

Clearly states the tool finds associated domains via shared registrant details or infrastructure. Distinguishes from siblings like securitytrails_subdomains and securitytrails_company_associated_ips by focusing on domain-to-domain association.

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?

Explicitly states it's for expanding scope from a single known domain to an organisation's wider estate. However, it doesn't contrast with alternatives like securitytrails_company_associated_ips or search_domains, which could also expand scope. The context is clear but lacks exclusions.

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