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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that the source is a public iTunes API and that Country/Lang select the storefront locale, but discloses no rate limits, quota, or pagination behavior beyond what the schema's defaults already state. Adequate but not rich.

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 waste. Purpose and required parameter are front-loaded, then the optional parameters are explained, then the sibling routing. Every clause earns its place.

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 100% schema coverage, an output schema present, and annotations covering the safety profile, the description supplies everything else the agent needs: purpose, locale scoping, pagination, and disambiguation from three sibling tools. Nothing material is missing.

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 coverage is 100%, so baseline is 3, but the description adds useful grouping semantics beyond the per-field schema text: Country and Lang jointly set the storefront locale, while Page and Limit jointly handle pagination. This helps an agent understand parameter relationships, not just individual fields.

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 (Search) and resource (Apple's public iTunes Search API for ebook results) and explicitly scopes it via the required Term. It also names the sibling tools it is not (audiobook_search, series, book), so an agent can select it without opening any 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?

Provides explicit when-to-use routing: 'Use apple_books_audiobook_search for audio editions, apple_books_series for series, or apple_books_book for one title's details.' This names the alternatives and the conditions that select each, leaving nothing to inference.

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