app_store_listing

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

With no annotations, the description carries the full burden and explicitly labels the operation read-only. It also discloses the unusual ratings source (public storefront lookup because App Store Connect exposes no aggregate rating) and that each entry names its source, which is genuinely useful behavioral context beyond the 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?

Three sentences with no filler, opening with the core operation and then covering ratings provenance and auth requirements. Every sentence carries operational information and the most important detail is front-loaded.

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 read-only tool with a full output schema and 100% parameter coverage, the description supplies purpose, behavior, authentication, and data provenance. Nothing needed to invoke it correctly is missing, and the output schema covers return-value expectations.

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?

All five parameters have detailed schema descriptions, so the baseline is 3. The description adds contextual meaning by tying name/subtitle/keywords to Apple's character limits and explaining why storefronts are used for ratings, but it does not map or extend individual parameter semantics beyond the schema.

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 names a specific verb (Read) and a concrete resource (App Store listing's indexed fields per locale, promotional text, version state, star ratings), which clearly distinguishes it from siblings like app_store_reviews or app_store_discovery. It also adds the meaningful constraint of checking against Apple's character limits.

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 its use through the list of read operations but never states when to choose it over alternatives or when not to use it. The auth-key requirement is operational context, not usage guidance. An agent would have to infer the appropriate context from the tool name and description alone.

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