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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds value by specifying that ratings are attributed to a third party (databazeknih.cz) and explaining what each ranking mode means (e.g., 'lowest live price among genuinely reviewed audiobooks'). This enriches the agent's understanding of the output.

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 states the core functionality and lists the options; the second provides usage context. No filler, no repetition. Every word serves a purpose. Front-loaded with key information.

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 tool's low complexity (2 params, enum-based, with output schema), the description fully covers what the agent needs. It doesn't need to explain return values because the output schema exists. The description is self-sufficient for this simple catalog-listing 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%, so the schema already documents both parameters. The description elaborates on the 'ranking' enum values with brief explanations (e.g., 'biggest-drops' - largest recent price drop), adding context beyond the enum labels. The 'limit' parameter is not described further, but the schema already covers it; thus the description adds moderate value.

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 specifies a clear verb ('get') and resource ('audiobook rankings'), enumerates the four ranking modes (cheapest, best-rated, biggest-drops, price-floor), and explicitly distinguishes from single-title tools by stating 'span the whole catalog, not a single title.' This leaves no ambiguity about the tool's scope.

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 explicitly tells when to use: 'Use for "best Czech audiobooks to buy now / cheapest / most discounted" queries that span the whole catalog.' It also implicitly excludes single-title queries, guiding the agent to other tools like get_audiobook. This provides clear when-to and when-not-to guidance.

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