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

Annotations already declare read-only, open-world, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds the loc.gov domain context but does not mention pagination behavior, rate limits, authentication needs, or result limits, which would be useful for a search tool.

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 tight sentences with zero waste, front-loading the core action and then the optional filters. It is appropriately sized for a search tool.

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?

The description is adequate for a read-only search tool with rich annotations and good schema coverage, but it leaves gaps: there is no output schema, and cursor-based pagination and the fact that q is optional are not explained. For a tool with five optional parameters, slightly more guidance would help an agent call 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 description coverage is 80%, so the schema already documents most parameters. The description reinforces the format and collection filters with examples, but adds little beyond what the schema provides for q, cursor, and per_page.

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 states a specific verb and resource: search Library of Congress digital collections on loc.gov, with optional format or collection filtering. It is clear what the tool does, but it does not explicitly distinguish itself from siblings such as loc_get_item or library_get.

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 implies usage for collection searching and notes optional filters, but it does not state when to use this tool versus alternatives or when not to use it. The collection parameter's reference to loc_list_collections is in the schema, not the description.

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