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

Without annotations, the description carries the full burden. It discloses that the tool makes one API call (efficiency) and clarifies the territorial scope and exclusions, which are important behavioral traits. It does not describe return format, but no output schema exists, so the gap is minor for a simple list.

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 description is two sentences plus a parenthetical, front-loaded with the core purpose. Every clause adds useful information: the resource, the sibling compatibility, the geographic scope, and the single-call nature.

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 zero-parameter list tool with no output schema, the description covers what is returned (province names), how they relate to other tools, and the key geographic limitation. Nothing an agent needs to call it correctly is missing.

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?

The tool has zero parameters, so there is no parameter semantics to explain. The baseline score of 4 applies, and the description appropriately avoids irrelevant parameter details.

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 clearly states it lists provinces of the Spanish cadastre and explicitly links the output to what sibling tools list_municipalities and list_streets expect as region. It also scopes the data to Spain only, excluding Basque Country and Navarre, which differentiates it from a generic list.

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 implies the tool should be used to obtain region names for list_municipalities and list_streets, and notes that Basque Country and Navarre are not covered. However, it does not explicitly state a workflow or say when not to use it beyond the geographic exclusion.

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