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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, but the description adds genuinely new facts: no network access, no stored state, deterministic output for identical input, a 1 s per-call latency budget, 64 KB input cap and 1 MB result cap. Those limits and the accent-insensitive all-words-AND matching rule are not derivable from the 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 Spanish text is front-loaded with clear labeled blocks (Cuándo, No para, Efectos secundarios, Determinista, Límites) and every line carries information. It is slightly bloated by re-stating the whole description in English inside the description field and by ending on a dangling truncated fragment ('[EN completo / full EN: inputSchema.description]').

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?

For a three-optional-parameter read-only lookup with an output schema, the description covers trigger, exclusion, matching semantics, side effects, determinism and resource limits. Nothing an agent needs to call it correctly is missing, and return-value detail is delegated appropriately to the output schema.

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% and each parameter already carries a description, so the baseline is 3. The description still adds semantics the schema does not spell out: the AND-matching and accent-folding behavior of name, and that country accepts an ISO 3166-1 code or a name in either English or Spanish.

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 gives a specific verb and resource (search a public list of ~10,000 universities) plus the exact return fields (name, country, domains, pages, total matches) and the matching rule (accent-insensitive, all words must match). It also explicitly separates itself from the sibling university-email-domain, so an agent can distinguish the two without opening either schema.

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 provides explicit when-to-use guidance ('hay que encontrar una universidad por nombre o país con sus dominios web') and an explicit not-for case pointing to the named alternative (university-email-domain). Both the positive trigger and the exclusion are stated, leaving nothing to inference.

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