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

With no annotations, the description carries the full behavioral burden. It conveys a read-only lookup via 'Check' and 'public', but does not disclose potential side effects, rate limits, authentication needs, or error behavior. This is adequate for a simple read tool but leaves gaps.

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 with no redundancy. It leads with the core action and resource, then lists the relevant fields, making efficient use of every word.

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 one-parameter tool with no output schema, the description adequately covers the tool's purpose and the types of data returned. It doesn't clarify error handling or output formatting, but these are minor for a lookup tool and are partly implied by the listed fields.

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 fully describes the sole parameter ('Domain name, e.g. example.com') with 100% coverage, so the baseline is 3. The description doesn't add parameter-level meaning beyond what the schema already provides; it only lists output fields, not parameter semantics.

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 specifies the verb 'Check', the resource 'public RDAP registration evidence for a domain', and enumerates the data fields (status, registrar, dates, registry information). This clearly distinguishes it from the sibling tools, which focus on companies, sanctions, and vendor preflight.

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 implies usage for domain registration checks but provides no explicit when-to-use guidance or when-not-to-use alternatives. It doesn't mention sibling tools or exclusions, leaving the agent to infer appropriate invocation.

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