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

Annotations already indicate readOnlyHint=true and destructiveHint=false. The description adds context about natural-language matching and examples, but it doesn't disclose behavioral details such as how results are ranked, whether filters like isFiction narrow results, or what the response shape looks like.

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 focused sentences convey the key use case, query style, examples, and the main alternative. Every sentence earns its place, and the most important guidance is front-loaded.

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 read-only tool with one required parametercandidate, the description gives enough context to select and invoke it correctly. Optional parameters are reasonably self-explanatory from their names and schema constraints, though the description could have briefly clarified 'isFiction'.

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 only 33%, with only the 'description' parameter documented. The tool description enriches that parameter with examples and wording, but it does not compensate for the undocumented 'isFiction' and 'limit' parameters, leaving their semantics largely to inference.

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's function: recommend books from a free-form description of mood, theme, or feeling. It explicitly differentiates from search_books, but does not directly address the sibling recommend_from_titles, leaving some differentiation to inference from the tool name.

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 gives concrete when-to-use guidance with examples such as 'books about grief' and 'cozy mysteries set in Cornwall.' It also names search_books as the alternative when title or author is known, but it doesn't mention when to prefer recommend_from_titles or other siblings.

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