Fear & Greed Index with history. $0.005.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"api_key": "<api_key>"
},
"name": "get_fear_greed"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| api_key | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full responsibility. It only hints at a cost ($0.005) but fails to disclose whether the tool is read-only, any rate limits, or side effects. The required api_key parameter is indicated in the schema but not explained in the description.
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 very concise (two sentences) and front-loaded with the tool's purpose. However, it omits critical information, making it too sparse for effective tool selection and invocation.
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 no output schema, no annotations, and two parameters with zero description, the description is severely incomplete. It fails to describe return values, behavior, or parameter meanings, leaving agents with insufficient context to use the tool correctly.
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 description coverage is 0%, and the description does not explain any parameters (e.g., what 'limit' controls or how to use 'api_key'). The description adds no value beyond the schema, leaving agents without guidance on parameter 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 'Fear & Greed Index with history' clearly indicates the resource, and the tool name includes 'get', making the purpose clear. However, it does not explicitly use a verb like 'retrieve' or 'fetch', and lacks differentiation from sibling tools, which are mostly distinct but not addressed.
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 usage guidance is provided. The description does not mention when to use this tool versus alternatives like get_social_sentiment or get_global, nor does it specify prerequisites or conditions for use.
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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