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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds a behavioral scoping detail: supports intraday (1-minute) through multi-year (5-year, max) ranges, which helps set expectations about data coverage. It does not disclose rate limits, data adjustment, or response format nuances, but given annotations cover safety, this is acceptable.

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, with the core purpose front-loaded in the first sentence. The second sentence provides concrete example queries, though three examples are somewhat redundant. Overall, it's efficient and scannable.

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 3-parameter tool with fully documented schema and no output schema, the description covers the essential behavior: what data it returns (OHLCV) and over what ranges. It doesn't describe exact return structure or time-series ordering, but there's no output schema and the tool is simple, so the description is sufficient for an agent to invoke 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 input schema has 100% description coverage: each parameter (symbol, period, interval) has a clear description with enums and defaults. The tool description does not add meaning beyond the schema; it only mentions '1-minute' and '5-year/max,' which mirror enum values. Thus baseline 3 is appropriate.

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 action and resource: 'Get historical stock price data' and explicitly lists OHLCV fields. It differentiates from sibling quote/search tools through the 'historical' qualifier and example queries like 'what was the stock price last month?'. However, it does not explicitly compare itself to stock_quote or other siblings, so it stops short of full differentiation.

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 gives clear context by providing representative user queries ('how has AAPL performed this year?', 'show me the price chart for Tesla') and explicitly says 'or any stock price history question.' It does not state when not to use it or direct to alternatives (e.g., current quote should go to stock_quote), so it lacks explicit exclusionary guidance.

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