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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is clear. The description adds key behavioral context beyond annotations: untracked apps return only a single recent day rather than a full window, which is valuable for setting expectations.

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 and well-structured: a dense first sentence states the core behavior, followed by a useful caveat and an example question. Every sentence earns its place with no redundancy.

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?

The output schema likely covers return values, and the description adequately conveys the tool's purpose and the untracked-app caveat. However, with five parameters and no schema descriptions, the lack of parameter guidance is a significant gap, especially for configuring countries/platforms and date windows.

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 0%, and the description does not explain individual parameters like countries, platforms, rangeDays, or end. The only implicit hint is that appStoreId identifies the app, but the format, defaults, and relationships between parameters are left undocumented, forcing the agent to infer from parameter names alone.

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 explicitly states the tool retrieves a country grid for a single app over a date window, including previous-window comparison and per-platform breakdown. This is a specific verb+resource that clearly distinguishes it from siblings like get_chart_top or get_app_history.

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?

It provides an example question ('Where does my app rank across Europe right now?') that signals the appropriate use case, and mentions that it works for untracked apps (with a caveat). However, it does not explicitly name alternatives or state when not to use this tool.

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