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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered; the description's 'Read-only' is largely redundant. The genuinely additive detail is the default-resolution behavior ('Defaults to the marketing version of the last pushed source'), which explains what version is actually read when the parameter is omitted.

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 short, front-loaded sentences with no filler: scope, default behavior, and the routing hint appear in that order. Every clause carries information.

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 two-parameter read tool with a 100% covered schema and an output schema, the description supplies everything an agent needs. Listing the returned fields is mildly redundant given the output schema, but it helps the agent confirm the tool's scope.

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% and both parameters are documented in the schema, so the baseline is 3. The description's note about defaulting to the marketing version restates the version_string schema description rather than adding new semantics, and the field list refers to outputs rather than inputs.

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 (Read) plus resource (the App Store listing for one iOS version) and even enumerates the fields returned (description, keywords, what's new, URLs, category, review contact). It is clearly separable from siblings set_metadata and get_metadata_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?

Explicitly routes the agent: 'Use it before editing with set_metadata,' establishing the read-before-write pairing with a named sibling. It gives clear context but stops short of stating when this is not the right tool (e.g., vs. read_store or get_metadata_schema).

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