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

Annotations already declare readOnlyHint and openWorldHint. The description adds important non-annotation behavior: the $0.002 USDC cost and no-charge failure when CoinGecko does not answer, plus minimum-market-cap filtering. It does not cover auth or rate limits, but the added cost and failure disclosure is substantial.

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 front-loaded with the core data and uses dense but informative phrasing. The long output-field list is justified because no output schema exists, and there is little filler, though it could be split for readability.

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 read-only, open-world data tool with no output schema, the description covers what is returned (category stats, top coins, weakest categories, breadth) and behavior (cost, failure, filtering). Combined with fully documented parameters and annotations, an agent has enough to invoke it correctly.

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 100%, so the schema documents all four parameters. The description still adds useful semantics by naming the ranking options, category examples, and min-market-cap filtering. It does not discuss limit, but the schema handles that.

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 states a specific resource and operation: sector-level crypto money flow ranked by 24h market-cap change or volume, with category stats and top coins. It is clear this is category-level rotation data rather than individual token pricing, though it does not explicitly name a sibling alternative.

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 explains what the tool returns and how kind/sortBy/minMarketCapUsd tune the result, but never states when to choose it over siblings such as crypto_sentiment or trending_tokens, nor when not to use it. Usage context is only implied by the term 'narrative rotation'.

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