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

Annotations already disclose the safety profile (read-only, idempotent, open-world, non-destructive), so the bar is lower. The description adds no additional behavioral details such as return shape, pagination, ordering, or empty-result behavior, but it does not contradict the annotations.

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 with no filler: the first states the core purpose, and the second delivers exactly the input guidance and examples an agent needs. It is front-loaded and every word 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 one-parameter read-only tool with safety covered by annotations, the description is nearly complete: it defines the input, gives valid examples, explains how to resolve slugs, and implies the return value (a list of books). It does not describe the return fields, but the low complexity makes this a minor gap.

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%, yet the description fully compensates by naming the parameter, explaining what an author slug is, listing concrete examples, and telling the agent how to discover valid slugs via resolve_name. This is strong parameter-level guidance.

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 action and resource ('List the books written by an author'), and the title reinforces the scope. It does not explicitly differentiate from sibling tools like list_book_titles or get_book_info, though the focus on an author slug makes the distinction inferable.

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?

It gives concrete usage guidance: pass an author slug and provides example slugs plus a resolution path via resolve_name type AuthorTopic. It does not state exclusions or when to prefer an alternative, but the context is clear and actionable.

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