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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context beyond those: it specifies the data source ('servicios.ine.es (INE Tempus3 API)'), states that no auth is required, and clarifies that the catalog has approximately 110 operations. This goes beyond the structured annotations without contradicting them.

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 with no wasted words. The primary action is front-loaded, examples follow, the filter-vs-list distinction is explicit, and the downstream integration with ine.tables is included. Every sentence earns its place.

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 tool with one optional parameter, a full output schema, and safe read-only annotations, the description is complete. It states the data source, authentication requirements, catalog size, filtering behavior, and the natural next step (ine.tables). No critical operational information 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 input schema already fully documents the single query parameter, including substring matching, case-insensitivity, examples, and omit-to-list-all behavior. The description largely restates this, adding only the clarification that the query filters by name or code. This is the baseline for 100% schema coverage: adequate but not additive.

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 opens with a specific verb and resource: 'Search or list Spanish INE statistical operations', and clarifies that this is the top-level catalog of official series with concrete examples like IPC and EPA. It is clearly distinct from data-retrieval tools such as ine.series.data and even names the follow-up tool ine.tables.

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 gives explicit modes of use: filter by query or omit to list all ~110 operations, and it directs the agent to pass the returned operation code to ine.tables. It does not explicitly contrast itself with the similarly named ine-spain.reference.operations or say when not to use it, but the Spanish INE and Tempus3 API identification provides useful selection context.

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