List collections

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral context: the row-per-collection output format (`[id] title`) and that offset enables paging, which the annotations do not convey.

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?

Front-loaded with purpose, then output shape, then alternatives, then args — a logical order with no wasted prose. The Args block slightly duplicates defaults already in the schema, but the added range justification 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?

For a read-only list tool with no output schema, the description supplies the missing return-format detail (`[id] title`), pagination guidance, and sibling routing. Nothing an agent needs to invoke it correctly is absent.

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 0%, so the description must carry the burden, and it does: it explains limit (range 1–500, default 200) and offset ('collections to skip, for paging'). The 1–500 range is meaningful added detail not present in the bare integer schema, though the default values merely repeat 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?

States a specific verb (List) and resource (all collections in the Apple Books library) with an explicit scope of 'all'. This cleanly distinguishes it from filtered siblings like search_collections_by_title and the detail-oriented describe_collection.

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?

Names the follow-up alternatives explicitly ('describe_collection(id) for details', 'get_collection_books(id) to list its books'), giving clear routing context. It does not state when to prefer search_collections_by_title over this enumeration, so it stops short of the full when/when-not bar.

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