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

No annotations are provided, so the description carries full burden. It discloses the tool is paid ($0.005), uses POST, and has no input parameters. However, it does not mention rate limits, caching, or output structure.

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 extremely concise with two sentences and a parenthetical, instantly conveying the purpose, interpretation, cost, and endpoint. Every sentence 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?

For a simple tool with no parameters and no output schema, the description is fairly complete: it explains the index range, contrarian nature, weekly trend, cost, and method. A minor gap is the lack of detail on the output format, but it's acceptable for a single-value return.

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?

With 100% schema coverage and no parameters, the description adds value by explicitly stating 'Send {}', confirming no input is required. This reassures the agent that no arguments are needed beyond the empty object.

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 that the tool returns the Crypto Fear & Greed index with a weekly trend, defined as a contrarian market-sentiment signal. This differentiates it from sibling prediction tools that focus on price or other metrics.

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?

No explicit guidance on when to use this tool versus alternatives like predict_market or analytics_indicators. The description merely notes it's a contrarian signal, which implies some usage but lacks direct when-to-use advice.

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