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

Annotations already provide readOnlyHint, destructiveHint, idempotentHint, openWorldHint, so the agent knows the tool is safe and read-only. The description adds useful context about public domain status (17 USC §105) and the types of content, enhancing transparency beyond annotations.

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 concise at three short sentences, front-loaded with the core purpose. Every sentence adds value: search scope, filter options, and legal status. No unnecessary words.

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 the tool has 5 parameters and an output schema, the description covers search scope, filters, and legal status. Pagination is handled by schema. It is complete enough for an agent to understand the tool's purpose and basic usage, though it could mention that results are paginated or include the total count.

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?

With 100% schema description coverage, the schema already describes all 5 parameters adequately. The description restates filter options (format and collection) but adds minimal new meaning beyond what's in the parameter 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 clearly states the tool searches 415K+ digitized historical items at LOC, listing specific item types (photos, manuscripts, etc.). It distinguishes from sibling tools like media.loc.collections (lists collections) and media.loc.item (gets item details) by focusing on search over the entire digitized corpus.

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 searching historical items with filters, but does not explicitly state when not to use it or mention alternatives like media.loc.item for individual details. However, the context is clear enough for an agent to infer appropriate use.

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