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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so safety is covered. The description adds genuinely useful behavior beyond that: the platform-dependent shape of returned records (helpful votes, developer reply, review title), which matters because there is no output schema.

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, zero filler. The returned-fields inventory is front-loaded and the platform caveat is attached where it is relevant, followed by the use case.

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 return fields and platform differences, which is the main completeness gap a caller would face. Pagination behavior, total counts, and whether reviews can be fetched beyond 30 are unaddressed, keeping it short of a 5.

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 100% — each of app_id, country, sort, and limit already documents format, enum values, and bounds. The description adds no parameter-level meaning beyond noting which platform a field comes from, so the baseline of 3 applies.

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?

States a specific verb and resource (get user reviews of an app) and then enumerates exactly what a review record contains: star rating, date, text, app version. It even documents platform-specific variance (helpful votes and developer reply on Google Play, review title on App Store), which lets an agent distinguish this from siblings like get_app or get_developer_apps without opening a schema.

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 closing sentence, "Use it to summarize what users like or complain about," gives a clear intended task context. There are no exclusions or named alternative tools, so the agent must infer that app metadata should come from get_app instead, but the positive guidance is unambiguous.

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