Crypto market indices (Fear & Greed, BTC dominance, euphoria)

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

Annotations already establish readOnlyHint=true and openWorldHint=true. The description adds useful behavioral context beyond that: values are live and refreshed roughly every 30 minutes, and Fear & Greed includes today and yesterday. It does not describe error behavior or exact freshness guarantees, but the added cadence detail is meaningful.

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?

It is a single compact sentence that front-loads the use case and enumerates the returned data points. Every clause contributes useful selection or freshness information, with no repetition of annotations.

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 zero-parameter read-only tool without an output schema, the description is nearly complete: it lists the main values returned and notes refresh cadence. It could be slightly stronger by clarifying the exact shape or units of the composite/dominance values, but nothing essential to invocation is missing.

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?

The tool has zero parameters and the schema is empty at 100% coverage, so there is no parameter semantics burden. The description correctly does not invent parameter details.

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 names specific indices (Fear & Greed, Bitcoin dominance, total market cap, Retail Euphoria) and a clear use context, so the agent knows exactly what data this tool returns. It does not explicitly contrast itself with similarly themed siblings such as get_altseason, get_cycle_indicators, or get_pressure_scores, which keeps it from a 5.

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 a clear trigger condition: 'when the user asks about overall crypto market sentiment or macro state.' That is strong usage context, but it offers no explicit exclusions or named alternatives for overlapping sentiment/macro tools.

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