top_charts

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

The annotation readOnlyHint=true already covers the read-only nature. The description adds value by specifying the daily rank movement and delta vs. yesterday, which implies historical comparison, but it does not disclose any other behavioral aspects like pagination, rate limits, or data freshness beyond the snapshot date. Since annotations are present, a score of 3 is appropriate as the description provides some extra context but not exhaustive.

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, well-structured paragraph that front-loads the core purpose, then explains parameters in a logical sequence. It uses commas and semicolons to separate ideas, making it readable without being verbose. Every sentence adds value, and there is 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?

Given the tool has 5 parameters, 100% schema coverage, and no output schema, the description compensates by listing the output fields (snapshot date, ranked apps with details) and explaining default behaviors for category and collection. It does not describe the output schema in detail, but since there is no output schema, the description provides enough context for an agent to understand what to expect. However, it might benefit from mentioning the response structure more formally, hence 4.

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 100%, and the description reiterates the parameter meanings (store, country, category, collection, limit) with clarifications like 'category' accepts OVERALL or genre IDs, and collection defaults. The description adds examples for category values, but the schema already describes these, so the marginal value is slight, justifying a baseline 3.

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 clearly states the tool gets a store top-chart ranking for a country, category, and collection, with daily rank movement. It specifies the return fields and distinguishes itself from sibling tools by detailing what it returns (rank, app_id, etc.) and how to specify categories and collections, which is more specific than sibling tools like list_top_chart_categories.

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 provides explicit usage guidance: how to choose between App Store and Google Play, category values (including default OVERALL and examples), and collection options (free, paid, grossing). It does not explicitly state when not to use this tool versus alternatives, but it clearly explains the input parameters, which is enough for selection among siblings like list_top_chart_categories.

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