etf_prices

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It only says 'Get historical price data' without any details about response format, potential limitations (e.g., date ranges, data availability), or that it's a read-only operation. This is a significant gap for a data retrieval tool.

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 sentence that is direct and free of fluff. It is appropriately short and the purpose is front-loaded. There is no unnecessary verbiage, making it a model of conciseness.

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 tool with 4 parameters and no output schema, the description provides only the bare minimum. It doesn't mention what the output looks like (e.g., time series), how the 'frame' parameter affects results, or what happens if date range is omitted. Given the rich sibling context, the description should at least clarify its scope and contrast with etf_quote. It's functional but not complete.

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 schema covers all 4 parameters with descriptions ('ticker', 'from', 'to', 'frame'), so parameter semantics are fully documented in the schema itself. The description adds no additional meaning beyond the schema, which meets the baseline for high schema coverage. However, it doesn't reinforce or exemplify the parameters, so it stays at baseline 3.

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 the tool's function: retrieving historical price data for an ETF. It distinguishes from siblings like etf_quote (current quote) and etf_gainers/losers (lists of movers) because historical data is a distinct concept, though it doesn't explicitly name those alternatives.

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 description provides no guidance on when to use this tool versus related siblings such as etf_quote, stocks_prices, or crypto_prices. It doesn't clarify that this is specifically for ETFs, nor does it mention the typical use case of historical analysis versus real-time quotes. The agent is left to infer the right context.

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