Qué cubre este MCP, y qué no

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

No annotations, so the description carries the burden. It states 'No consulta la red' (a real behavioral trait an agent needs), discloses that the full output is long, and that results are pre-packaged indexes with a generation date. It does not describe the response shape or performance, but the safety/behavioral profile is well covered.

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?

Front-loaded with the core purpose, then usage guidance, then a note about behavior. Four tight sentences, each earning its place. The final clause about the full table being 'largo' is slightly redundant but useful for output-size expectations.

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 single-parameter, no-output-schema, metadata-listing tool with no annotations, the description covers purpose, when to use, network behavior, and the parameter's effect. The only gap is that it does not hint at the return structure (e.g., that it lists per-source coverage and index dates), which is minor given no output schema requirement.

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, but the description adds genuinely useful semantics: passing `fuente` returns ONLY that source's scope, which the description notes is what is typically needed, versus the long full table without it. That is practical guidance beyond the enum/description in the schema.

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 and object ('Declara el alcance real: qué fuente responde cada pregunta') and clearly distinguishes itself from the many buscar_* siblings by declaring it is about coverage scope, not retrieval. An agent can tell what this tool does versus buscar_por_tema or buscar_unificado without opening the 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?

Explicitly says when to use it: 'Úsala ANTES de concluir que algo "no existe" a partir de una búsqueda vacía' and to check index freshness. It also gives the selection rule for the parameter. This is exactly the when/when-not guidance the dimension rewards.

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