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

Annotations already show readOnlyHint=true and destructiveHint=false, and the description complements them by revealing what the tool inspects: headline 30-day count, spike-resistant usage estimate, busy-day share, version-flood bursts, and a clean/unreliable/inflated verdict. It also explains the underlying supply-chain technique, giving the agent meaningful expectations beyond what the annotations provide.

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 compact enough while carrying substantive context: a one-sentence definition, a concise explanation of the attack pattern, a list of returned metrics, and an explicit usage directive. Every sentence serves a purpose, though the attack-technique explanation is slightly verbose relative to the core actionable content.

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 one parameter, no output schema, and no siblings, the description fully carries the burden of explaining what the agent can expect. It names all key outputs (count, spike-resistant estimate, busy-day share, version bursts, verdict) and gives clear invocation context, so nothing essential is left undocumented.

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 covers the single parameter 'package' with a clear description and example, so the baseline is 3. The description reinforces that the package is an npm package name but does not add new parameter-level detail such as format constraints or validation rules, so it neither improves nor detracts from schema coverage.

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 opens with a specific verb and resource: 'Check whether an npm package's public download count reflects real adoption.' It goes beyond a generic statement by naming the exact threat ('download pumping') and enumerating the returned verdicts, so an agent knows precisely what the tool does even with no sibling tools to contrast against.

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 gives an explicit usage instruction: 'Use before adding or recommending a dependency, especially a new or unfamiliar one.' This establishes clear when-to-use context, though it does not discuss when not to use the tool or compare it to alternatives — but no sibling tools exist, so the omission is minor.

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