top_countries

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

Since no annotations are provided, the description carries full responsibility for disclosing behavioral traits. It does not mention whether the operation is read-only, any rate limits, error handling, or the structure of the response. It only describes the purpose and parameters, leaving the agent to guess at side effects or limitations. This is a significant gap for a tool with no annotation support.

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 highly concise: a single purpose sentence followed by a clean parameter list. It is front-loaded with the core purpose and then provides exactly the needed parameter explanations. No unnecessary words or repetition.

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 that an output schema exists, the return format is already defined and need not be described. However, the description does not cover any behavioral context (e.g., whether app_id and product_id are mutually exclusive, how the date range is interpreted, or any limitations on limit/days). For a simple ranking tool this is acceptable, but it leaves some ambiguity. Overall, it is adequate but not comprehensive.

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 description adds meaningful explanations for each parameter beyond the schema: 'metric: Which metric to rank by,' 'limit: How many countries to return,' 'days: Look-back window,' 'app_id: Restrict to one store listing,' 'product_id: Restrict to one product.' The schema provides types and defaults but no descriptions, so the description compensates well. However, it could be slightly more specific (e.g., clarifying that metric is from an enum, but the schema already shows that).

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 states a clear purpose: 'Ranked countries for a metric over a date range.' It specifies the resource (countries), the action (rank), and the context (metric and date range). This distinguishes it from sibling tools like overview or metrics, which likely have broader or different scopes.

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 no guidance on when to use this tool versus alternatives like metrics, timeseries, or overview. It only lists parameters without any 'use this when' or 'for X use Y' context. An agent would have to infer that this tool is for country-level ranking, but no explicit comparison or usage scenario is given.

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