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

There are no annotations, so the description must cover behavioral traits. It only states it returns download counts, but doesn't mention that it queries the npm registry, whether it requires network access, rate limits, or the format of results. It also doesn't clarify if the counts are for a specific package or all packages, or if historical data is included. That's minimal disclosure.

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 extremely concise (one line) and front-loads the core purpose. However, it's so brief that it sacrifices essential details. It earns a 4 for being efficient, but it's borderline under-specified.

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?

Given the tool has an output schema but no parameter description, the definition is incomplete. It doesn't explain the input format, expected output structure, or any error conditions. For a tool that likely queries npm registry, it leaves too much to inference.

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 0%, meaning the description is the only source of parameter meaning. It doesn't explain what the 'q' parameter should contain – a package name, a scope, a version? The description only implies 'q' is related to npm downloads, but without schema details, the agent is left guessing.

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 'npm Downloads: npm download counts day/week/month' clearly indicates the tool reports npm download counts for various periods, but it doesn't specify the exact resource (e.g., package name) beyond the 'q' parameter. It is distinguishable from siblings like npm, npmorg, npmpkg which focus on other npm aspects, but the phrasing is not as specific as it could be.

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 guidance is given on when to use this tool versus alternatives. There is no mention of what 'q' should contain (package name? package name with scope?) or how it differs from siblings like npmdownloads (which might be a different variant). Context implies it's for download stats, but that's not explicit.

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