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

With no annotations, the description carries the full burden and does disclose the key behavioral traits: this is a free, partial scan (only 3 of 9 checks) whose result is a sample of a paid product, and it returns JSON. Auth requirements, rate limits, and whether the URL is fetched live are left unstated, keeping it below a 5.

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?

Two tight sentences, front-loaded with the free-preview framing and the check breakdown, with no filler. "Returns JSON" is justified because there is no output schema.

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 single-parameter, no-output-schema read tool, the description conveys the scope limit and return format adequately. Return-value structure is only named, not detailed, but the absence of an output schema makes that a minor gap.

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 100% and the single url parameter is fully documented in the schema, so the baseline is 3. The description lists what gets checked but adds no new meaning about the parameter itself (format, constraints, redirect handling).

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 concrete verb+resource (free preview of a website audit) and scopes it precisely as 3 of 9 checks, which implicitly separates it from the full-audit siblings audit_site/deep_audit. It does not name those siblings, so the differentiation is inferable rather than explicit.

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?

"Use it to see the shape of the result before paying" gives a clear usage condition (pre-purchase exploration) that routes the agent away from a full audit. It stops short of naming the paid alternative or stating exclusions, so it is clear context without explicit alternatives.

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