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

The readOnlyHint annotation already establishes safety, and the description adds useful context about the data scope and threshold. It does not disclose output size, sorting behavior, or whether gainers and losers are returned separately, but for a parameterless read-only list this is a mild gap rather than a serious one.

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 a single compact phrase that front-loads the key concepts: 24h gainers, losers, and trend candidates. The parenthetical threshold adds precision without extra words, and every component 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 parameterless read-only tool, the description provides enough context to understand what results will represent and to choose the tool correctly. Minor missing details such as the number of entries returned or quote currency do not affect the ability to invoke it, since there are no parameters and the read-only annotation covers the safety profile.

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 input schema is empty, so there are no parameter semantics for the description to clarify. The baseline score of 4 applies because schema coverage is trivially complete and no invocation arguments are needed.

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 the resource: ranked 24h gainers, losers, and trend candidates with a >+5% move threshold. It does not use an explicit action verb like 'returns' or 'lists,' and it does not explicitly distinguish itself from sibling tools such as market_trending, though the 24h movers framing implies a different purpose.

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?

The intended usage is implied: an agent should use this for recent price movers over 24 hours with significant percentage changes. However, there is no explicit guidance about when to prefer this over alternatives like market_trending or market_overview, and no exclusion criteria are stated.

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