npm_downloads

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

No annotations are provided, so the description carries the full burden. It reveals that this is a read-only count lookup scoped to one package and three time windows, but says nothing about caching/freshness of counts, whether scoped packages (@scope/name) are supported, or rate limits. Adequate for a simple read, but thin.

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 front-loaded sentence with zero filler. It is arguably under-specified rather than over-long, but nothing is wasted.

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 2-parameter read tool with no output schema and no annotations, an agent still cannot tell what is returned — a single integer, or a series of daily counts for last-week/last-month. That ambiguity affects how results should be interpreted, so the description is adequate but has a real 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 description coverage is 100%, so the schema already documents both 'name' and 'period'. The description merely echoes the three period values and adds no format or example details beyond what the schema provides.

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+resource ('Download counts for an npm package') and the available time windows. It is distinguishable from npm_search / npm_get_package / npm_dist_tags by name and subject matter, though it never explicitly contrasts itself with them.

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?

No indication of when to use this versus the other npm tools (search, get_package, dist_tags, whoami) or any preconditions. The only usage-adjacent content is a restatement of the period options, which is already in the schema, not a routing rule.

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