news_categoriesList crypto news category tags available for filtering the news feed (BTC, ETH, Trading, Regulation, Mining, etc.). Use as a directory before calling news() with a category filter.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {}
+]Output schema / (root)Previous value: -nullNew value: +{
+ "description": "Available news categories",
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds context by explaining it returns tags and lists examples, though it doesn't disclose how the list is ordered or if it's exhaustive. No contradictions.
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?
Two sentences, each serving a distinct purpose: stating the action with examples, and providing usage guidance. No filler words.
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 simple listing tool with no parameters and an output schema, the description is complete. It tells what it returns, gives examples, and explains how to use it in a workflow.
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 tool has no parameters, so the baseline is 4. The description provides no parameter information (unnecessary) but adds value with examples of category values.
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 includes a specific verb ('List'), a clear resource ('crypto news category tags'), and concrete examples (BTC, ETH, Trading, etc.). It distinguishes itself from sibling tools like 'news' by focusing on categories rather than the feed.
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?
Explicitly states to 'Use as a directory before calling news() with a category filter', providing direct guidance on when and how to use this tool in conjunction with another.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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