sentiment

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

With no annotations, the description carries the full behavioral burden, and it does disclose the auth/cost profile ('Free, no signup required') and the upstream data source. However it says nothing about rate limits, caching/freshness of the index, or the shape of the returned reading, so meaningful gaps remain.

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 core sentence is tight and the example is useful, but 'Free, no signup required' is duplicated verbatim, wasting space in an otherwise short description. Front-loading the bracketed API tag before the actual purpose is also slightly backwards.

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 one-optional-parameter, no-output-schema tool, the description covers source, cost, and return content (current reading plus optional history) adequately. It stops short of describing the fields in the reading, but the complexity here is low enough that this is close to sufficient.

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 100% and the single limit parameter is already documented there as optional with default 1 and max 90. The example URL reinforces usage but adds no semantics beyond the schema, so the baseline 3 applies.

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?

Identifies a specific resource and source: the Crypto Fear & Greed Index from alternative.me, returning the current reading plus optional history. The verb is implicit ('get'), and it is clearly distinguishable from numeric siblings like price, funding_oi, or long_short_ratio, though it never explicitly frames itself as a retrieval operation.

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?

There is no when-to-use guidance and no alternatives named, which matters in a sibling set full of sentiment-adjacent signals (long_short_ratio, momentum_score, kalshi_probability). The only contextual cue is 'Free, no signup required', which speaks to accessibility, not to tool selection.

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