publishersList public-sector publishers on datos.gob.es (Spanish open data portal); returns publisher names and IDs, up to 50 results.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No |
| Name | Required | Description | Default |
|---|---|---|---|
| results | No | Array of publisher objects |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "limit": 10
+ }
+]Output schema / (root)Previous value: -nullNew value: +{
+ "description": "List of publishers from datos.gob.es",
+ "properties": {
+ "results": {
+ "description": "Array of publisher objects",
+ "items": {
+ "properties": {
+ "description": {
+ "description": "Publisher description",
+ "type": "string"
+ },
+ "id": {
+ "description": "Publisher identifier",
+ "type": "string"
+ },
+ "name": {
+ "description": "Publisher name",
+ "type": "string"
+ }
+ },
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds useful context beyond annotations: limits results to 50, returns specific fields. Annotations already indicate safe read, and description aligns with 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?
Single, front-loaded sentence with no wasted words; efficiently conveys purpose, scope, and constraints.
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?
Covers purpose, output fields, and limit. With an output schema present, doesn't need to detail returns further. Minor omission: limit parameter optionality not stated.
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?
Description implicitly explains the 'limit' parameter by stating 'up to 50 results', adding meaning beyond the schema's bare type. With 0% schema coverage, this compensates well.
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?
Clearly states verb 'List', resource 'public-sector publishers', specific source 'datos.gob.es', and output details (names, IDs, up to 50 results). Distinguishes from siblings as no other tool lists publishers.
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?
Implied usage for listing publishers from Spanish open data portal, but lacks explicit guidance on when to use or not use, and no alternatives mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.