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

Annotations already declare readOnlyHint and destructiveHint, so the description does not need to reiterate safety. However, it adds valuable behavioral context: 'best-rated' uses third-party rating from databazeknih.cz and is attributed, and 'cheapest' filters to genuinely reviewed audiobooks. This enriches understanding beyond 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: the first quickly defines the tool's function; the second provides usage guidance. No wasted words, front-loaded with purpose.

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?

With output schema present and annotations covering safety, the description covers the ranking types, catalog scope, and use cases adequately. It fully informs an agent for selecting this tool.

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 100%, and the description adds nuance to the 'ranking' parameter by explaining what each option means (e.g., 'lowest live price among genuinely reviewed audiobooks' for cheapest). This adds value beyond the schema descriptions.

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 returns catalog-wide audiobook rankings for specific metrics (cheapest, best-rated, biggest drops, price floor). It explicitly distinguishes from sibling tools like get_audiobook or search_audiobooks by specifying the scope and purpose.

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 provides explicit guidance: 'Use for "best Czech audiobooks to buy now / cheapest / most discounted" queries that span the whole catalog, not a single title.' This tells the agent when to use this tool and implies when not to use it.

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