Get a snapshot of any App Store app to analyze competitors. Retrieve ratings, reviews, version, price, category, and release notes by name or ID.
Look up any app on the App Store: ratings, reviews, version, price, category, release notes. Search by name or App Store ID. Pro feature.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | App name (e.g. "Medisafe") or numeric App Store ID | |
| country | No | Two-letter country code (default: us) |
Changes observed during successful MCP inspections.
v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. 'Look up' clearly implies a read-only operation, and the listed fields indicate no side effects. However, it doesn't disclose behaviors like rate limits, error handling for not-found apps, or what the return format looks like, and the 'Pro feature' is vague about enforcement.
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?
Two sentences, front-loaded with the action and data fields. Every word earns its place, including the 'Pro feature' note. No fluff or redundant detail.
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?
For a simple 2-param lookup without output schema, the description covers the main purpose and return fields. It doesn't mention default country or pagination/limits, but these are either in the schema or minor for the tool's simplicity. Overall sufficient 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?
The schema already documents both parameters (query as app name/ID, country as two-letter code) with 100% coverage. The description's 'Search by name or App Store ID' repeats the schema's query description, adding no new semantic value.
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 a specific action ('Look up any app on the App Store') and lists the data provided (ratings, reviews, version, price, category, release notes). It distinguishes from siblings like app_details by emphasizing 'any app,' implying competitor or third-party lookup.
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 gives clear context: it's for looking up any app, which implies use for competitor research. It mentions search methods (name or App Store ID), but doesn't explicitly state when not to use it or name alternatives like app_details. The 'Pro feature' hint adds some context about access.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.