search_books

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

The annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable behavioral context by noting that it 'Uses Open Library,' implying an external dependency with potential variability, and explains the index-based performance difference between parameter types.

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 purpose, the second delivers the key usage tip. No redundant or filler content; every word earns its place.

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 search tool with an output schema and 100% parameter documentation, the description covers the essential aspects: what it does, the external data source, and parameter preferences. It doesn't mention full-text vs. metadata matching or potential API limitations, but these are minor given the existing structured context.

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?

The schema has 100% coverage with descriptions for all parameters, but the description adds semantic nuance by explaining why title/author are preferred ('dedicated indexes') and frames query as a fallback. This goes beyond the schema's 'recommended' labels by explaining the underlying reason.

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 opens with 'Search for books by title, author, or free text,' which clearly specifies the action (search) and the resource (books). It distinguishes from sibling tools like search_papers (which searches papers) and get_book (which retrieves a specific book).

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 clear internal guidance: 'Prefer title and author over query — they use dedicated indexes and return far better results.' This tells the agent which parameters to favor for better outcomes, though it doesn't explicitly contrast with sibling tools beyond the tool name and purpose.

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