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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds that the tool excludes full text and price, and notes that price varies by country on the website, giving some extra behavioral context beyond annotations. It still omits details like authentication, rate limits, or pagination.

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 two compact sentences with no wasted words. The first phrase restates the title, which is slightly redundant, but overall the structure is front-loaded and efficient.

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 retrieval tool with no output schema, the description partially covers return contents but misses the action verb and any parameter explanation. It also does not clarify how the required slug is used or how the locale parameter affects the response, leaving notable gaps.

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 50%, with the slug parameter having no description at all. The description does not mention either parameter, so it fails to compensate for the missing slug guidance and adds no meaning beyond what the schema already provides.

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 opens with the title repeated ('Fiche d'un livre') and then enumerates the content returned (presentation, themes, links, free extract), implying retrieval. However, it never states an action verb (e.g., 'retrieve', 'fetch') and does not differentiate itself from sibling tools like search_books.

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 provides negative usage boundaries by explicitly stating what the tool does not return ('Pas de texte intégral, pas de prix'), which hints at when not to use it. But it never names an alternative tool or states positively when this tool is the right choice.

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