Get price history (sparklines)

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

Annotations already declare readOnlyHint and openWorldHint, so the description adds value beyond them by providing concrete behaviors: the ~90-day lookback, 50-ticker limit, interval options and their meanings, and the return type (close prices only, not OHLCV). This is useful context that goes beyond the structured annotations.

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 two sentences long, front-loaded with the primary purpose and key constraints, and contains no redundant wording. Every clause adds information about the data scope, granularity, or output shape, making it highly efficient.

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?

With no output schema and relatively simple inputs, the description covers the essential behavior: time range, ticker limit, interval effect, and return type (close prices per ticker). It does not detail output ordering, missing data handling, or error cases, but for a straightforward data-retrieval tool, the provided information is adequate for an agent to select and 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?

The schema covers 50% of parameters (only interval has a description), but the description enriches both: it restates the ticker limit (already in schema) and, more importantly, expands the interval enum with plain-language meanings ('1d daily, 1wk weekly, 1mo monthly'). This compensates for the schema gaps, though ticker format is not detailed.

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 tool as returning historical price series for up to 50 tickers over ~90 days, with a specific use case for charting or trend/return computation. It distinguishes itself from sibling tools by explicitly stating it returns close prices only, not full OHLCV data, which separates it from quote tools.

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 implies when to use the tool by mentioning charting and trend/return analysis, and clarifies a limitation ('not full OHLCV') that helps rule out alternatives. However, it does not explicitly name alternative tools for different use cases, nor state scenarios when this tool should be avoided, so it stops short of full explicit guidance.

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