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

Annotations only declare readOnlyHint and openWorldHint; the description adds real behavioral context by disclosing the specific external sources consulted (state regulator tracker, public RDAP) and by explicitly warning the output is probabilistic signals rather than a verdict. It omits rate limits, auth needs, and failure behavior for unreachable or unregistered domains.

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?

A single dense sentence with the core purpose front-loaded, followed by a short caveat. Every clause carries information (distinct signal categories) and there is no filler.

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 correctly takes on the job of describing what the tool returns by enumerating the signal categories. It is nearly complete for a two-parameter read tool; only output shape (scored fields vs. raw evidence) and the relationship between url and text remain unstated.

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 50%: the 'text' property is documented, but 'url' is not. The description compensates partially by explaining that pasted text is scanned for regulator-listed red-flag phrases, which clarifies the optional parameter's intent, but adds no format or constraint detail for the required url parameter.

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?

States a specific resource (a website) and enumerates the concrete signals returned: regulator scam-tracker matches, look-alike domain detection, RDAP domain age, HTTPS, and red-flag phrases. This is far more informative than a tautology, though it never names the sibling search_scams or explains how it differs from it.

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?

Usage is implied clearly enough (an agent knows this is the per-URL scam-signal lookup), and 'Signals, not a verdict' usefully frames how to treat the output. However, there is no explicit when-to-use versus when-not guidance and no routing to alternatives like search_scams or compare_bots.

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