npm stats: downloads

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds the important behavioral constraint that the window is fixed at 7 days (no range parameter) and previews the returned fields. It doesn't mention caching, rate limits, or how missing packages are reported.

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?

Three short sentences, front-loaded with the core action and window, followed by the disambiguation and the return shape. 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 describes the return fields (package, downloads, start and end dates), and the single required parameter is covered by the schema. Nothing an agent needs in order to call it and interpret results is missing.

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 single `name` parameter is fully documented in the schema, including scoped-package examples like '@types/node'. The description adds nothing beyond 'npm package' — which is adequate but purely baseline given 100% 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?

States a specific verb (get download counts) and resource (npm package) with a scoped window (last 7 days) and frames the metric's meaning as a popularity signal. It also names the sibling npm_package and what that one is for, so an agent can distinguish the two without opening schemas.

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?

Explicitly routes version/license lookups to npm_package, giving a clear alternative with the condition that selects it. It lacks guidance on when download counts are or aren't the right popularity signal versus other sources, but the core alternative is stated.

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