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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no extra behavioral traits such as rate limits, required authentication, or response size. It primarily lists output contents and id format, which are more about purpose and parameters than behavior, so it doesn't go beyond the annotations.

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 two sentences and efficiently packs the tool's purpose and key parameter semantics. The first sentence gives a comprehensive but focused list of output fields, and the second clarifies the id format with examples. No redundant or filler content.

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?

With no output schema, the description compensates by enumerating the major response fields (rating histogram, version history, IAP flag, etc.). Combined with solid annotations and clear parameter descriptions, it gives the agent a strong understanding of what to expect. Minor omissions like error behavior or missing fields for certain stores are not critical given the annotations and the tool's read-only nature.

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 covers 100% of parameters with descriptions, including the id format (Apple trackId or Google package name). The description repeats the id explanation but adds concrete examples (6448311069, com.whatsapp) that clarify the expected format. No other parameters gain new meaning beyond what the schema already provides.

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 opens with 'Full details for one app' and provides an extensive list of returned data fields (description, version, release dates, rating, etc.). It clearly identifies the tool's specific function (fetching comprehensive app details) and distinguishes it from siblings like get_app_datasafety and get_app_reviews by being the general-purpose detail fetcher.

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 makes the tool's use case clear: retrieving complete app metadata for a single app. However, it does not explicitly mention alternative tools for narrower queries (e.g., get_app_reviews for reviews) or provide when-not-to-use guidance. The context is clear but lacks explicit exclusions or referral to siblings.

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