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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: the output arrives as a PDF attachment or a download link valid for 24 hours, a summary is also returned, and the report is branded and points to scplus.es. These delivery/link-lifetime details are exactly the kind of trait annotations do not capture.

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 compact sentences, front-loading the deliverable before the return format and the optional-field note. Every clause carries information; the only minor slack is that the branding/link detail could be trimmed, but it is not padding.

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 12-parameter, 9-required tool with no output schema and a nested 'titulares' array, the description does the important work of explaining what is returned (PDF plus summary) and how it is delivered. The enums and field-level requirements are self-documenting in the schema, so the remaining gap — no guidance on how the viability/prescoring inputs are derived — is modest.

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 only 50% across 12 parameters, so the description should compensate more than it does. It does add real meaning for 'nombre' — that it is optional and only personalizes the first line, and that surnames, DNI and contact data are not required — but the remaining parameters are left entirely to 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?

The description names a specific verb and deliverable ('Genera un informe en PDF') and specifies its contents (viabilidad + prescoring) plus branding and an external link. It is clearly distinguishable from the sibling calculators by being the report/deliverable generator, but it never names or contrasts an alternative, so it stops short of full sibling 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?

Usage is implied rather than stated: an agent infers this is the final reporting step that packages viability and prescoring, but there is no explicit when-to-use, when-not-to-use, or pointer to mortgage_evaluar_viabilidad / mortgage_prescoring_perfil as the tools that compute the inputs. The clarification about what data is not needed (apellidos, DNI, contacto) partially guides invocation without routing it.

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