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

Annotations already establish read-only, idempotent, non-destructive behavior, so the description only needs to add useful context. It adds the data source (servicios.ine.es Tempus3 API), confirms no auth required, and states the return value's role. This goes beyond the annotation basics.

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?

Three sentences deliver the essential information: purpose, search behavior, output use, data source, and auth. Every sentence contributes value and the main purpose is front-loaded.

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 optional parameters, both fully documented in the schema, and an output schema present, the description covers the remaining context: how to use the result, what data source it pulls from, and that no authentication is needed. Nothing critical is missing for correct invocation.

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. The description adds meaningful behavior for the search parameter: case-insensitive substring filtering, example values, and clarifies that omitting it returns the full list. The lang parameter is already fully described in the schema enum.

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 ('Browse'), a resource ('catalog of 109 published Spanish official statistical operations'), and gives concrete examples (IPC, EPA). It further clarifies the output's intended use by stating it returns operation_code for use in ine-spain.tables, which distinguishes it from related INE tools.

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?

The context is clear: this is a reference/browse tool serving as a starting point before fetching data from ine-spain.tables. It also informs the agent that search is optional and how to filter. It does not explicitly list alternatives or exclusions, but the workflow hint is enough to communicate its purpose.

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