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

No annotations are provided, so the description carries the full burden. It discloses the requirement for country_code, the fallback behavior, and the data returned (ranks, movement, curves, tokens). However, it does not explicitly state that the operation is read-only or mention any side effects, permissions, or rate limits. For a get-style tool, this is acceptable but not exhaustive; a 3 is appropriate.

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 concise—two sentences—and front-loaded with the core purpose. It avoids redundancy with the schema and packs essential routing and output information into a compact space. There is no wasted verbiage.

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?

Although there is no output schema, the description explicitly lists the return data (current/best/previous ranks, movement, hourly rank curves, game tokens). It also mentions the need to consult the filter tool for valid categories and country selection, covering important prerequisites. It does not elaborate on pagination behavior, but the schema already covers limit/offset, so this is acceptable. Overall, it is complete enough for an agent to invoke 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?

Schema coverage is 100%, so the baseline is 3. The description adds meaningful value beyond the schema: it highlights that country_code is mandatory and directs users to get_store_game_rank_filter for valid categories and country selection, which enriches the understanding of those parameters without repeating their schema descriptions.

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 specific verb ('Get'), the resource ('official Google Play or iPhone App Store charts'), and the key parameters (free/paid/grossing, day/week/month, category). It clearly distinguishes itself from the sibling filter tool by name, leaving no ambiguity about what this tool retrieves.

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 explicitly says when to use this tool vs. the alternative: 'country_code must be explicitly specified by the user; otherwise get_store_game_rank_filter and ask for the country.' This provides clear conditional routing and names the fallback tool, which is exemplary guidance.

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