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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety/external-source profile is covered. The description adds the upstream source (alternative.me) and the shape of the returned data, which is useful. It does not disclose refresh cadence or how stale the 'latest' value may be, which matters for a live indicator.

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 short clauses with zero waste: the data identity and contents come first, the caveat last. Every element earns its place.

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 input parameters and no output schema, the description carries the burden of describing the return payload and does so (value, classification, 7-day history). The only gap is timing/freshness, which an agent would want for a market indicator.

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?

Zero parameters, so there is nothing for the description to disambiguate; baseline is 4. The schema also declares additionalProperties: false, consistent with a no-argument fetch.

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?

States a specific verb-less but precise retrieval: the Crypto Fear & Greed Index from alternative.me, with the value range (0-100), classification, and 7-day history. An agent knows exactly what it gets. It does not explicitly contrast itself with any sibling, though none of the listed siblings overlaps with a crypto sentiment index.

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?

'Indicator, not advice' signals intended use as a sentiment input rather than a trading directive, but there is no explicit when-to-use, when-not, or pointer to an alternative (e.g., get_market or get_current_regime for regime context). Usage is only implied.

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