getFearAndGreedIndex

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states it 'retrieves' data, implying a read-only operation, but doesn't clarify aspects like rate limits, authentication needs, error handling, or the format of the returned value (e.g., numeric score, timestamp, classification). For a tool with no annotation coverage, this leaves significant gaps in understanding its behavior and constraints.

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 a single, efficient sentence that directly states the tool's purpose without any fluff or redundant information. It is front-loaded with the key action and resource, making it easy to parse quickly. Every word earns its place, and there's no wasted verbiage.

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 the tool has 0 parameters, 100% schema coverage, and no output schema, the description is minimally adequate. It specifies what data is fetched but lacks details on return format, error conditions, or usage context. For a simple read-only tool, this might suffice, but without annotations or output schema, the agent has incomplete information about what to expect from the response.

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 0 parameters, and schema description coverage is 100%, so there are no parameters to document. The description doesn't need to compensate for any parameter gaps. A baseline of 4 is appropriate as the description accurately reflects the lack of inputs, though it doesn't explicitly state 'no parameters required,' which would warrant a 5.

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 clearly states the action ('Retrieves') and the specific resource ('current Fear and Greed Index value from Alternative.me API'), making the purpose unambiguous. It doesn't explicitly differentiate from sibling tools, but given the unique nature of this index among mostly blockchain-related tools, differentiation is somewhat inherent. However, it doesn't explicitly contrast with similar data-fetching siblings like 'getCryptoPrice' or 'getStats', so it falls short of a perfect 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 provides no guidance on when to use this tool versus alternatives. It doesn't mention any prerequisites, context for usage, or comparisons to sibling tools like 'getCryptoPrice' (which might fetch other market indicators) or 'getStats' (which could include broader statistics). The agent must infer usage based solely on the tool name and description without explicit direction.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.