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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description's only additional behavioral fact is the 'newest first' ordering. It says nothing about result size, pagination, or whether an unknown author returns empty.

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 short, front-loaded sentences with no fluff. The opening 'Books Like This.' merely restates the title/name and earns no place, which is the only real inefficiency.

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 read-only lookup with no output schema, the agent has everything needed to invoke it: what it returns (an author's books), their ordering, the required parameter, and intent examples. Minor gaps on result volume and no-result behavior are acceptable here.

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% – both 'author' and 'country' (with its US/GB/IE/CA/AU values) are documented in the schema. The description adds no parameter-level detail beyond the example author names. Baseline 3 is correct when the schema does the heavy lifting.

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+resource: it lists an author's books, ordered newest first. Clear and distinct from bookslikethis_find_similar_books and bookslikethis_get_book, but the sibling relationship is never made explicit, so the agent must infer the difference.

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?

"Use for 'what has Andy Weir written?' or 'Sally Rooney's books'" gives concrete user-intent triggers that make the when-to-use condition clear. It stops short of naming alternatives or stating when NOT to use it (e.g. for a single title, use get_book).

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