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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint true, and destructiveHint false, so the safety profile is clear. The description adds that the tool is 'first-class' on both stores, which is useful context about cross-store behavior, but does not disclose other behavioral traits such as potential empty results or rate limits.

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 a single, concise sentence that front-loads the core purpose ('Customers also bought' / related apps) and adds the key detail about store support. Every word contributes value, with no unnecessary filler or repetition of schema details.

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 tool is a simple read-only retrieval operation with five parameters, two of which are required, and no output schema. The description covers the purpose and key context (cross-store support), and the schema covers parameter details. It is adequately complete for an API of this complexity, though it could mention output format or pagination behavior, but that is not critical given the simple 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?

Schema description coverage is 100%, so the input schema fully documents all five parameters including meanings for id, store, lang, limit, and country. The description does not add parameter semantics beyond what the schema already provides, so the baseline score 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?

The description uses a clear verb+resource: it retrieves 'Customers also bought' / related apps for one app. It differentiates from sibling tools like get_app or get_app_reviews by specifying the 'similar apps' scope, and the mention of 'both stores' adds specificity.

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 implies the tool is used to fetch related apps for a given app, but does not explicitly state when to use it over alternatives or when not to use it. No sibling tools or exclusions are mentioned, leaving guidance at a basic implied level.

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