Zovo Domain Lookup

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

Annotations already declare readOnly/idempotent/openWorld/no-destructive, so safety is covered; the description goes beyond that with real behavioral caveats — data is live from registries, personal data is usually redacted, and a not-found result does not mean the domain is buyable. Those are non-obvious traits that materially change how an agent should interpret and report results.

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?

Trigger phrases and the return payload come first, exclusions last — good front-loading with no filler sentences. The first sentence is a long comma-chained list of trigger phrases, which is dense to parse but each element is functional.

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 define return shape, yet it still summarizes the key fields (registrar, dates, days left, status codes, nameservers, DNSSEC, abuse contact, sorted CSV) so the agent knows what to surface. Combined with documented parameters and strong annotations, nothing needed for correct invocation is missing.

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 description coverage is 100% and the single 'domains' parameter is fully documented there (separators, length limits, URL handling, IDN support). The description only echoes the batch cap of 20 and does not add format or separator guidance, so schema-coverage baseline 3 applies.

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 names a specific verb and resource ('whois lookup or a domain lookup') and immediately bounds scope: up to 20 domains, live RDAP registry data. It also distinguishes itself from adjacent capabilities by naming what it is not (IP lookups, DNS resolution, uptime, SSL checks), so an agent can tell it apart even without siblings.

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?

It gives concrete user phrasings that should trigger the tool ('who owns this domain', 'when does my domain expire') and an explicit exclusion list at the end. The coverage caveat ('Only TLDs that publish an RDAP service') and the not-found caveat tell the agent when a result is not authoritative, which is exactly the routing guidance needed.

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