get_trending_books

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

Annotations already declare readOnlyHint and openWorldHint, so the 'Read-only' restatement adds little. However, the description adds real behavioral context beyond the annotations: ranking order (most popular first), pagination via limit/offset, and the exact return envelope and fields, which lets an agent plan consumption of results.

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?

Three short sentences, all front-loaded: purpose, semantics, then disambiguation. No filler, and the sibling routing comes last where it belongs.

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?

No output schema exists, and the description compensates by naming the return shape ({returned, offset, books}) and key book fields. Combined with 100% parameter coverage and annotations, an agent has everything needed to call and consume the result.

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 each parameter is documented with defaults and bounds, so the schema carries the semantics. The description mentions 'duration' default 'week' and limit/offset pagination, which largely repeats the schema rather than adding new meaning (e.g., ordering interplay with offset, or how duration buckets are computed). Baseline 3 applies.

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?

States a specific verb and resource ('books trending on Hardcover'), plus scope details (time window, popularity ranking, pagination). Explicitly distinguishes itself from get_vibes and search_books, so an agent can route without opening schemas.

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?

Gives explicit alternatives with the condition that selects each: 'For curated themed collections use get_vibes; for a custom query use search_books with sort=users_count:desc.' That is exactly the when-to-use-this-vs-alternatives guidance the dimension rewards.

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