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

No annotations are provided, so the description carries the full behavioral disclosure burden. It usefully states the index range and that history can span up to a year, but it does not mention read-only behavior, data freshness, rate limits, or authentication requirements. For a low-risk data retrieval tool this is adequate, but not thorough.

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, both front-loaded with essential information: the first defines the metric, scale, and history; the second gives usage guidance. There is no redundant or filler text.

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 a low-complexity tool with one optional parameter and an output schema, the description is nearly complete. It covers the index meaning, scale, and history range; the output schema handles return values; only explicit parameter mapping and safety context are slightly under-explained.

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%, so the single 'days' parameter is documented only by its name and default. The description partially compensates by mentioning 'up to a year of daily history,' which implies that the parameter controls how much history is returned, but it does not explicitly map the parameter to days of history or state valid ranges.

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 identifies a specific resource – the Crypto Fear & Greed Index – and explains its scale (0–100) and historical scope (up to a year of daily data). It does not explicitly differentiate this tool from related siblings like crypto_market_overview, but the index itself is distinctive enough that an agent can identify what it does.

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?

It gives clear usage context: 'Use as a market-sentiment signal for trading, newsletters or answering how the crypto market feels.' This tells the agent when the tool is appropriate, though it does not name alternatives or state when not to use it.

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