etf_gainers

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

No annotations are provided, so the description carries the full burden of disclosing behavior. It only states that the tool 'gets' gainers, but does not reveal what data is returned (e.g., list of tickers, percentage changes), any limitations (e.g., time period, market), or whether it's a read-only operation. For a tool with zero annotation coverage, this is a significant gap.

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, concise sentence that front-loads the core purpose. There is no wasted text, and every word adds value. It is efficient without padding.

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 the tool's simplicity (no params, no output schema, no annotations), the description is minimally adequate, but it lacks key context such as what 'top' means, any time horizon, or what the output looks like. Sibling tools like etf_losers imply symmetry, but the description alone does not fully equip an agent to interpret or use the result 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?

The tool has zero parameters, so the baseline is 4. The description needs no param explanations, and the schema is empty. It is fully self-contained in this regard.

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 verb ('Get') and a clear resource ('top ETF gainers'). It is not a tautology because 'top' adds meaning, and the name itself distinguishes ETFs from other asset classes. However, it does not explicitly differentiate from sibling tools like etf_losers or other gainers tools, and it leaves 'top' ambiguous (e.g., by daily change, volume, etc.), so it doesn't fully meet the 5-level bar for distinguishing from siblings.

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?

There is no guidance on when to use this tool versus alternatives. For instance, it does not mention that this is for identifying ETFs with the largest gains in a given period, nor does it contrast with etf_losers or other asset-class gainers. An agent would have to infer the use case from the name alone.

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