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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered; the description adds genuinely new behavior: it returns pages with título, sección and URL plus text passages, and stamps each page with the date it was read (freshness signal). It does not discuss ranking, failure/empty-result behavior, or whether the site is Spanish-only, which keeps it below a 5.

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, front-loaded with scope, then return shape, then usage rule — no filler. The long parenthetical topic list is dense but each item conveys real coverage the agent can match a question against.

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 does the work of explaining the return payload (titles, sections, URLs, answering passages, read dates) and states the scope boundary. What remains unstated — result ordering, behavior when nothing matches, whether read_page is the expected follow-up — are minor gaps for a 2-parameter read-only search.

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 100% and both parameters (query with min/maxLength and examples, limit with 1-10 range and default 6) are documented in the schema itself. The description adds no extra parameter guidance, so the baseline 3 applies.

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?

Names the verb (Busca), the scope (TODO el sitio) and enumerates the content types covered (guías, herramientas/calculadoras, glosario, directorios, páginas de datos). This clearly separates it from the vertical search siblings like search_products, search_rentals and search_used_cars, which cover only one content type each.

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 an explicit negative rule ("cualquier pregunta que no sea buscar avisos") plus a concrete job-to-be-done ("saber a qué página mandar a la persona"), which effectively routes the agent toward this tool over the classifieds searches. It never names an actual sibling tool or states when to prefer them, so the routing is inferable rather than prescribed.

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