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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It states the output is download totals, but it does not mention whether the tool requires specific input formats, how it handles invalid crate names, whether it returns historical data or just current totals, or the response structure. This is a significant gap for a simple lookup tool.

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 a single sentence and short, which is concise. However, it is too terse and omits necessary details, so conciseness comes at the cost of completeness. The information is front-loaded but minimal.

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's simplicity (one parameter, no output schema details), the description should explain the input and output clearly. It fails to mention what 'q' represents, whether it is required, and what the output format is. The tool is incompletely specified for an agent to use correctly.

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 input schema has a single parameter 'q' with a default of '' and no description. Schema description coverage is 0%. The description mentions 'Download totals' but does not explain that 'q' is likely the crate name, nor does it clarify the expected format (e.g., exact name vs. partial). The description adds no value in explaining the parameter.

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 'Crate Downloads: Download totals for a Rust crate' states a specific purpose but is brief. It does not clearly distinguish from similar tools like 'npmdownloads' or 'crates', though the emphasis on 'download totals' and 'Rust crate' provides some specificity. The title is almost identical to the name, adding little.

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?

There is no guidance on when to use this tool versus alternatives such as 'crates' or 'cratestats', which likely provide crate metadata. The description implies a simple query for download counts but does not mention any prerequisites or limitations (e.g., whether it supports historical data or only current totals).

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