themesList available dataset themes/categories on datos.gob.es (e.g. Economy, Health, Transport); returns theme labels and IDs for use as a filter in the datasets tool.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No |
| Name | Required | Description | Default |
|---|---|---|---|
| results | No | Array of theme objects |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "limit": 20
+ }
+]Output schema / (root)Previous value: -nullNew value: +{
+ "description": "List of themes from datos.gob.es",
+ "properties": {
+ "results": {
+ "description": "Array of theme objects",
+ "items": {
+ "properties": {
+ "description": {
+ "description": "Theme description",
+ "type": "string"
+ },
+ "id": {
+ "description": "Theme identifier",
+ "type": "string"
+ },
+ "title": {
+ "description": "Theme title",
+ "type": "string"
+ }
+ },
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds that it returns labels and IDs for filtering, which is useful but not extensive. It does not discuss pagination or rate limits.
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 a single sentence that is front-loaded with the action and resource, containing no wasted words. It efficiently conveys purpose, examples, and usage context.
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?
Given the tool's simplicity (one optional parameter, output schema present, strong annotations), the description covers the main points: what it does, where it applies (datos.gob.es), and its role as a filter. Missing parameter guidance is a minor gap.
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 has 0% description coverage for its only parameter 'limit'. The description does not mention or clarify the 'limit' parameter at all, leaving the agent without guidance on its meaning or usage.
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 the verb 'List' and the resource 'dataset themes/categories' on datos.gob.es, with examples (Economy, Health, Transport). It distinguishes itself from the sibling 'datasets' tool by specifying its use as a filter.
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 description tells the agent to use this tool 'as a filter in the datasets tool', providing clear context. However, it does not explicitly mention when not to use it or alternatives beyond the implicit distinction from 'datasets'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.