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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine behavioral context beyond that: every figure carries its source, differences are only returned when both sources publish the value, and small municipalities substitute a county average with an explicit label. Minor gap: no note on partial-data cases beyond the county-average rule.

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 metric list is front-loaded and every clause conveys substance. The full Spanish repetition doubles length for readers who only need one language, which is a real cost, though it is a deliberate bilingual-serving choice rather than filler.

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 steps in to explain the return shape (per-metric value plus source plus difference) and the small-municipality caveat, which is the main thing an agent needs. It is nearly complete; only edge cases like unresolvable municipality names are unaddressed.

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 property is described with name-or-slug guidance and the language enum, so the schema carries the burden. The description only implies that two municipality identifiers are compared; it adds no format, ambiguity-resolution, or disambiguation guidance beyond 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 concrete verb+resource (side-by-side comparison of two municipalities) and enumerates the exact dimensions compared: price per m², IBI, rent, commute minutes, beach, rent-cap zone, tourist flats, resident satisfaction. The two-input scope implicitly separates it from single-municipality siblings like ficha_municipio, but no sibling is named, so the differentiation is left to inference.

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?

Framed around 'what weighs most when choosing', which hints at the residential-decision use case, but there is no explicit when-to-use, when-not-to-use, or pointer to alternatives such as ficha_municipio for a single town or municipios_similares for discovery. Usage must be inferred from the metric list.

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