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

The description adds valuable behavioral context beyond annotations: the 20-book limit, specific output fields (for_readers, against_readers, mood, themes), and link formatting requirements. However, it fails to explain the destructiveHint=true annotation—what data is modified/deleted when 'getting' details—leaving a significant behavioral gap.

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 is front-loaded with the core purpose and efficiently structured. The presentation guidelines earn their place as they specify required output formatting. Minor deduction for the typo 'showing showing' and slightly verbose link example.

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?

Given the single parameter with full schema coverage and no output schema, the description adequately compensates by detailing expected return fields (for_readers, against_readers, etc.) and presentation requirements. It would benefit from explaining the destructive annotation or return value structure.

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?

With 100% schema description coverage ('The book IDs'), the baseline is 3. The description adds the constraint that up to 20 IDs can be processed and implies they originate from explore_books, but doesn't specify ID format, syntax, or validation rules beyond 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?

The description clearly states the tool 'Get full details for up to 20 books' with specific verb, resource, and quantity limit. It explicitly distinguishes from sibling 'explore_books' by noting these are IDs 'as returned by explore_books', establishing the workflow relationship.

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?

The description implies the intended workflow by referencing 'explore_books' as the source of IDs, and provides specific presentation guidelines (what fields to show, link format). However, it lacks explicit 'when not to use' guidance or comparison to alternatives like 'list_bookmarked_books'.

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