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

No annotations are provided, so the description carries the full burden, and it delivers real operational context: data is served from a '30-minute cache' (staleness/latency expectation) and is free for commercial use with attribution (licensing constraint the agent may need to surface). It does not cover failure modes or rate limits, so it is not exhaustive.

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, front-loaded with what is returned before the use cases and provenance details. Dense and largely waste-free, though the promotional framing ('The most-cited single market-sentiment gauge') is persuasion rather than instruction.

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?

With no output schema and no annotations, the description has to describe the response itself, and it does — value range, the five classification labels, and optional history. It is sufficient for correct invocation; only the `limit` semantics and error/timeout behavior are left unstated.

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 single `limit` integer is undocumented in the schema. The phrase 'optional daily history' implies limit controls how many days of history are returned, which adds real meaning, but it never states units, default, or range, so the mapping remains inferred rather than specified.

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?

Names a specific resource and provider ('Crypto Fear & Greed Index by alternative.me') and enumerates exactly what it returns: a 0-100 value, a named classification band, and optional daily history. This is unmistakably distinct from the sibling utilities (domain-lookup, email-verify, fx-rates, etc.), so an agent can select it without inspecting the schema.

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?

Gives concrete usage contexts — 'position sizing, risk checks and regime detection before trading' — which tells the agent when this signal is relevant. It stops short of explicit exclusions or naming an alternative tool, but the siblings are unrelated utilities so no routing conflict exists to resolve.

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