Retrieve 'Customers Also Bought' audiobooks for a given Apple Books audiobook ID. Returns related titles from the catalog page.
Retrieve "Customers Also Bought" audiobooks. Returns the related audiobooks shown on the Apple Books catalog page.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Apple Books numeric audiobook ID | |
| lang | No | Result language tag | |
| country | No | Two-letter storefront country code |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden. It uses read-only language ('Retrieve', 'Returns') and specifies the data source (Apple Books catalog page), clearly indicating a non-destructive operation. It does not mention edge cases like empty results or pagination, but overall it communicates the core behavior.
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 consists of two concise sentences, front-loaded with the main action. Every word serves a purpose, with no fluff or repetition.
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 simple retrieval tool with three well-documented parameters and no output schema, the description adequately states purpose and return concept. It could clarify that the result is a list, but 'related audiobooks' implies a collection. Overall, it is complete enough for this tool's complexity.
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?
The input schema already provides 100% coverage with clear descriptions for id, lang, and country. The description adds no parameter-specific details beyond the schema, so it meets the baseline but does not exceed it.
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 clearly states the tool retrieves 'Customers Also Bought' audiobooks, with the verb 'Retrieve' and specific resource. It distinguishes from sibling tools like apple_books_audiobook_search (search) and apple_books_book_similar (books) by focusing on related audiobooks.
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?
Usage is implied by the description and name: use this to get related audiobooks for a given audiobook. However, it does not explicitly mention when to avoid it or how it compares to related tools like apple_books_audiobook or apple_books_audiobook_series.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.