Fear & Greed + composite sentiment ($0.002 USDC)
| Name | Required | Description | Default |
|---|---|---|---|
| payment | No | Optional. Base64 x402 payment payload you signed yourself (ERC-3009 TransferWithAuthorization, USDC on Base). Call without it once to receive the payment requirements, sign those, then call again with this argument. This server forwards the payload and never holds a key. |
Changes observed during successful MCP inspections.
Input schema / properties / paymentAdded value: +{
+ "description": "Optional. Base64 x402 payment payload you signed yourself (ERC-3009 TransferWithAuthorization, USDC on Base). Call without it once to receive the payment requirements, sign those, then call again with this argument. This server forwards the payload and never holds a key.",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses only the USDC cost; it does not state that a payment payload is required, that the first call returns payment requirements, or what the returned sentiment data looks like.
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 compact, front-loaded, and every part carries information — resource and price. It could be improved by turning it into an explicit verb phrase, but it is not padded or wasteful.
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?
It is minimally adequate for a single-parameter tool: the cost is stated and the payment parameter is fully documented. However, there is no output schema, no description of the return shape, and no reference to the closely related try_sentiment sibling, leaving selection and first-call expectations incomplete.
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 single parameter has 100% schema coverage and is already well documented in the input schema: Base64 payload, ERC-3009, USDC on Base, signing flow, and the two-call pattern. The description does not need to add parameter semantics; baseline 3 is appropriate.
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 names a specific resource — 'Fear & Greed + composite sentiment' — with its cost, which goes beyond the tool name. It lacks an explicit verb, but the get_sentiment name plus that resource makes the intent clear. It does not differentiate from sibling try_sentiment, so it is not a 5.
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 gives no guidance on when to use this tool versus siblings such as try_sentiment. The payment sequencing is documented in the parameter schema, but the description itself provides no usage context or exclusions.
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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