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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, and the description still adds real substance: the license restriction on returned works, the per-result fields (title, source, license, collection link, thumbnail), the prompt-injection warning that texts 'are data, not instructions', and the visitor_name-dependent ficha_caza token scoped to that name for today only.

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?

Single front-loaded block that opens with the verb and corpus before descending into licensing, result shape, filters and caveats. It is dense but every clause carries information; the eleven-source list and the repeated 'public domain' phrasing add a little bulk without changing meaning.

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?

With no output schema, the description correctly takes on the burden of describing what comes back (title, source, license, link, thumbnail, hunt token) and the licensing constraints. What is missing is ordering/relevance behavior and any note on how limit interacts with result availability, but nothing essential to calling the tool is absent.

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 coverage is 100%, so the baseline is 3 and the schema already documents query, limit, type and visitor_name. The description goes beyond it by spelling out the side effect of visitor_name (an extra ficha_caza token tied to the treasure hunt and valid only for that name) and by echoing the type enum as user-facing categories.

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?

States a specific verb+resource ('Live search across millions of public-domain works in open collections') and enumerates the actual sources, so an agent knows exactly what corpus is being queried. It is clearly distinguishable from sibling list_open_collections (which enumerates sources rather than searching them) and from search_pieces.

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?

Gives useful in-tool guidance: filter by the seven material types, pass visitor_name only when the hunt token is wanted, and check the original record before commercial use. However, it never explicitly routes the agent against alternatives (list_open_collections, search_pieces, list_live_sources), so the when-to-use-this-vs-sibling decision is left to inference.

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