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

Annotations already mark readOnlyHint=true and destructiveHint=false, and the description adds non-obvious behavior: the recursive smoothing is warmed up on price history before startDate, so output doesn't depend on the requested range's left edge. It also clarifies the unit (USD), which is useful behavioral context.

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?

Four dense sentences, each informative: definition, formula, use case, and behavior. No filler; the technical description is front-loaded.

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?

No output schema exists, and the description doesn't explicitly state the return shape, but the maxResults parameter description covers record ordering and count. The description provides the essential interpretive and behavioral context (unit, warmup, volatility interpretation) needed to use the tool confidently.

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?

Schema description coverage is 100%, so the baseline is 3. The description adds value by explaining that period is a smoothing window used recursively and that startDate's left-edge warmup makes values stable; this goes beyond the schema's terse 'Start date in YYYY-MM-DD' definition.

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 opens with 'Average True Range (ATR) for a stock' and unpacks the indicator with a precise formula (True Range max of high-low, |high-prev_close|, |low-prev_close|), distinguishing it from related indicators like Bollinger Bands or Stochastic Oscillator. The scope is clear: a volatility measure for a single stock, in USD.

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 states ATR is 'commonly used for position sizing and stop placement' and explains that higher ATR means wider daily moves, giving clear applied context. It doesn't explicitly name alternatives or when-not-to-use, but the domain is sufficiently specialized.

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