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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context by explaining what each kind returns and which parameters are required for word_count, going beyond the annotations without contradicting them.

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 compact and scannable, with four short lines, clear mode names, and a helpful example. It contains no filler and front-loads the mode names, making it easy for an agent to quickly identify the relevant kind.

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?

The description gives enough detail for word_count but is incomplete for text_availability, where the book identifier is not specified, and it does not clarify the full parameter requirements for links_between_categories. Since there is no output schema, more explicit invocation details would be needed for full completeness.

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 0% schema description coverage, the description must carry the parameter documentation burden. It explains the kind enum and maps word_count to title, version_title, and language, but it leaves links_between_categories implicit regarding category_a/category_b and does not specify which parameters text_availability needs.

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 defines three distinct statistic kinds with concrete meanings and an example, so an agent can understand what the tool computes. It does not explicitly distinguish this tool from sibling getters like get_book_info or get_text_versions, but the 'statistics' scope and bulleted kinds make the purpose reasonably clear.

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 gives per-kind guidance, such as 'needs title, version_title, language he/en' for word_count, and an example for links_between_categories. However, it does not explicitly say when to prefer this tool over sibling tools or state any excluded use cases, leaving most selection logic to inference.

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