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

Annotations already establish read-only, idempotent, open-world behavior, and the description adds genuinely new context beyond them: first_archived is null when no snapshot exists, archive.status signals archive.org failure, and notes are explicitly 'not flags'. These edge-case disclosures are exactly the kind of behavioral detail the annotations cannot convey, though rate limits or latency are unmentioned.

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?

It is a single dense but front-loaded sentence that leads with the primary outputs before the caveats. Every clause carries information, though packing return-value semantics, error states, and notes semantics into one run-on sentence slightly hurts scannability.

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 no output schema, the description carries the burden of explaining returns and does so for the main fields plus null/unavailable edge cases. It is nearly complete for a single-parameter lookup, though it omits any note on response shape or whether lookups can be partial.

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 parameter is fully documented as accepting a 'Domain, URL, or email address', so the baseline is 3. The description adds no syntax or format detail beyond the schema, but none is needed.

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 enumerates the specific data resources returned — registration date/age, registrar via RDAP, email-auth records (MX/SPF/DMARC), and a Wayback first-snapshot date — which is far more than a restatement of the name. It distinguishes itself from siblings like company_profile and screen_sanctions, though it never states an explicit verb ('retrieves'/'reports'), leaving the action inferrable rather than declared.

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 framing 'common fraud signals' implies a due-diligence/investigation use case, but there is no explicit when-to-use statement and no named alternative among the sibling tools (due_diligence_report, screen_sanctions, company_profile). Usage is implied rather than guided.

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