Search the catalogue

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

The description reveals important non-obvious behaviors over and above the annotations: filters that match nothing are dropped and announced, online_only defaults to true, and each result carries an identifier for get_item. It contradicts none of the provided hints and adds meaningful operational context.

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?

The description is a single dense paragraph with no fluff; every sentence conveys a distinct fact about the tool's behavior, defaults, or usage. The main purpose is stated first, and the organization makes it easy to scan.

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 12 parameters, an output schema, and sibling tools, this description covers all critical aspects: scope, required parameter rationale, exclusions, filter behavior, defaults, and the link to get_item. Nothing essential is missing for safe and effective use.

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?

Despite high schema coverage, the description enriches understanding of several parameters: it explains why media_type is required (separate catalogues), that subject/location/language/collection need the Library's exact vocabulary, and what online_only=false means. This goes well beyond the schema field descriptions.

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 the Library of Congress catalogue' and explicitly lists the media types included, making the verb and resource unmistakable. It also names the sibling tool search_newspapers as the alternative for full-text scanning, which clearly distinguishes this 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?

It gives an explicit exclusion: 'use search_newspapers for a phrase printed on a newspaper page', and explains when to set online_only to false. It also notes that controlled-vocabulary fields use the Library's own terms, guiding correct usage.

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