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

Annotations declare readOnlyHint and openWorldHint, but the description adds real behavioral context: results are capped at 50 and cover only the first page, and tags are user-generated with no enumerable directory. It doesn't discuss pagination options or response shape, but the truncation limit is the key trait an agent needs.

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 tight sentences, front-loaded with the action and scope, then the parameter caveat, then the alternative routing. No filler.

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 an output schema present, return values need not be described. The description covers the result cap, the parameter nature, and sibling alternatives — everything needed to select and invoke it correctly.

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 already documents the single `name` parameter, so baseline is 3. The description adds that the tag is user-generated, gives a concrete example (`fantasy`), and clarifies there is no directory to look up valid slugs, which goes beyond the schema text.

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 (fetch) and resource (book items from a Goodreads genre/shelf tag's Top Books page) with explicit scope (up to 50 items). It is clearly distinguishable from sibling tools like goodreads_search and goodreads_list.

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?

Explicitly routes the agent: use goodreads_search for title or author queries, and goodreads_list for a Listopia list's ranked books. It also warns there is no complete genre directory, so the agent knows it must supply a known slug.

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