Historical WHOIS

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=falseching, so the description need not restate safety. It adds useful context by noting each record includes the observation window and that historical records may reveal previously redacted registrant details, but it does not go deeper into rate limits or data availability.

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 two sentences with no filler. The first sentence defines what the tool does Bennett, and the second explains why historical data is valuable. Both earn their place and the key operational detail ('past WHOIS records', 'window it was observed in') is front-loaded.

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?

For a simple read-only tool with only one required parameterebb, the description is largely complete: it explains the purpose, the result type (past records with observation windows), and the likely motivation for using it. The lack of an output schema is partially offset by the mention of observation windows and the response_format parameter.

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 description coverage is 100% for both parameters, so the baseline is 3. The description does not add additional meaning beyond what the schema already explains for 'domain' and 'response_format'.

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 states a specific verb and resource: 'Retrieve past WHOIS records for a domain.' The word 'Historical' in the title and 'past' in the description clearly contrast with the sibling tool 'securitytrails_whois_current', so an agent can distinguish the two, though the description does not explicitly name the sibling.

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 gives a concrete use case: historical records may expose registrant details that are now redacted. However, it does not explicitly say when to use this tool instead of the current WHOIS tool, nor does it mention exclusions or alternatives.

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