package_downloads

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

Annotations already declare readOnlyHint:true and openWorldHint:true, so the safety profile is known. The description adds 'Free, no payment required,' which is a helpful behavioral trait beyond annotations. However, it does not disclose the ecosystem-specific behavior of the 'range' parameter (e.g., PyPI returns only last-week, crates.io returns a 90-day total), leaving that to the schema. This is not a contradiction but a moderate gap.

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 two short sentences, front-loaded with the core action, and contains no unnecessary filler. Every word adds value.

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 read-only tool with no output schema and full parameter schema coverage, the description is adequate. It clearly states the core purpose, and the schema fills in the ecosystem-specific range behavior. It does not mention return format or limitations beyond what's in the schema, but neither is required for such a straightforward use case.

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%, with detailed descriptions for all three parameters, including the important caveats about 'range'. The description itself adds no parameter-specific meaning beyond what the schema provides, so the baseline 3 is appropriate.

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 uses a specific verb ('Get') and resource ('download counts for an npm, PyPI or crates.io package'), making the tool's functionality immediately clear. It also distinguishes itself from sibling tools like package_snapshot, package_vulns, and package_deps, which address different concerns.

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 states what the tool does but offers no explicit guidance on when to use it over alternatives or when not to. The sibling names (snapshot, vulns, deps) make the comparison obvious, but the usage context is implied rather than directly stated.

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