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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by listing what the response contains (dates, price, address and coordinates, full description, web page), which matters since there is no output schema. It does not address failure modes such as an invalid or expired plan identifier.

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?

A single front-loaded sentence: the resource is named first, then the returned fields are enumerated. There is no filler or redundant phrasing. It is tight but terse enough that it omits guidance entirely.

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 only two parameters at 100% schema coverage and no output schema, the main gap would be return-value explanation, and the description fills exactly that by listing the fields returned. What is missing is usage routing relative to buscar_planes, which is a modest but real gap for a detail-fetch tool.

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 the schema itself explains that «plan» accepts either a value from buscar_planes or a listing URL, and that provincia is unnecessary when a URL is supplied. The description adds nothing about the parameters, 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?

The description states the resource precisely ("Los detalles de un plan") and enumerates the concrete fields it returns (próximos días, precio, lugar con dirección y coordenadas, descripción completa, ficha web), so an agent can tell this is a single-item detail lookup rather than a search. It never explicitly names buscar_planes as the sibling it differs from, so it stops short of full differentiation.

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?

There is no when-to-use or when-not-to-use guidance in the description and no mention of alternatives such as buscar_planes or listar_provincias. The only workflow hint (that «plan» comes from buscar_planes) lives in the schema, not in the description, leaving the guidance burden on structured fields.

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