mlb_get_divisionsList all MLB divisions with IDs, names, and leagues for mapping teams and standings. Filter results with the optional fields parameter to keep only needed keys.
List all MLB divisions with their IDs, names, and associated leagues.
| Name | Required | Description | Default |
|---|---|---|---|
| fields | No | Keys to keep (comma-separated). |
Changes observed during successful MCP inspections.
v1.4.1Input schema / $schemaRemoved value: -"http://json-schema.org/draft-07/schema#"Input schema / properties / fieldsAdded value: +{
+ "description": "Keys to keep (comma-separated).",
+ "type": "string"
+}v1.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description contributes the fact that this returns the complete set of divisions with their IDs, names, and leagues, which partially compensates for the absent output schema, but says nothing about the fields parameter or result ordering.
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?
One sentence, front-loaded with the verb and resource, with every clause carrying information (IDs, names, associated leagues). Nothing wasted and nothing buried.
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-required-parameter read-only list tool with no output schema, stating the returned fields is the key compensation and it does that. It is only slightly incomplete in not clarifying the 'fields' projection behavior or whether results span both leagues.
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% for the single optional 'fields' parameter, so the schema already documents its purpose ('Keys to keep (comma-separated)'). The description adds no extra meaning to that parameter, which is the baseline 3 case.
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?
States a specific verb (List) and a specific resource (MLB divisions), plus the fields returned, so it is trivially separable from siblings like mlb_get_teams or mlb_get_standings. It stops short of naming an alternative, but the resource itself is unambiguous.
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?
No when-to-use guidance, no prerequisites, and no mention of alternatives. The agent must infer from the resource name alone that this is the lookup for division metadata rather than team or standings lookups.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.