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

With no annotations, the description must carry the burden of behavioral disclosure. It mentions the required inputs and default period but omits output format, array-length constraints, and edge-case behavior; it also contradicts the empty input schema by asking for parameters the schema does not define.

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 front-loaded sentence that moves from purpose to required inputs. The 'Atr:' prefix is redundant with the tool name, but otherwise every clause contributes.

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 empty input schema and absent output schema, the description is too thin to guarantee correct invocation. It fails to explain how arrays should be structured, how the period interacts with data length, and what the returned ATR value looks like.

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 declares zero parameters, yet the description supplies the essential parameter names (high/low/close arrays, period) and the default of 14, which is meaningful added value. However, it stops short of specifying types or the mechanism for passing these inputs given the empty schema, so it does not fully compensate.

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 'Calculate Average True Range (ATR), a volatility indicator,' giving a specific verb and resource. This clearly distinguishes it from sibling technical-indicator tools such as x402-rsi or x402-macd.

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 gives input guidance (high/low/close arrays, optional period) but frames it only as a calculation tool. It does not state when ATR is preferred over alternative indicators or name any exclusions, so selection among the many sibling tools is left to inference.

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