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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds valuable behavioral context beyond annotations: the lookback window is warmed up on price history before startDate, so values don't depend on the range's left edge. This helps agents understand why results may differ from naive computation. It doesn't disclose return format, but for a read-only indicator with no output schema, this is solid.

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 four sentences of high-density information: what it is, formula components, use case, and a key computation nuance. Every sentence earns its place with no redundancy. It is front-loaded and easy to scan.

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 technical indicator with configurable parameters, the description covers the core semantics, usage, and a critical warm-up behavior. The absence of an output schema is mitigated by explaining the indicator's components. It could mention the return rows (e.g., date, %K, %D) or percentages, but overall it is sufficiently complete for an agent to understand what to expect.

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 coverage is 100%, so the description doesn't need to explain each parameter. The description does add conceptual meaning by defining %K and %D in terms of the lookback window and smoothing, which relates to kPeriod and dPeriod, but it doesn't directly enrich parameter syntax or constraints. 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 opens with 'Stochastic Oscillator (%K and %D) for a stock,' clearly identifying the tool as a specific technical indicator. It then explains what %K and %D measure, distinguishing it from other indicator tools like GetAverageTrueRange or GetBollingerBands. The purpose is concrete and unambiguous.

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 states 'Useful for spotting overbought (>80) and oversold (<20) conditions,' providing clear guidance on when the tool is appropriate. It does not explicitly mention alternatives or exclusions, but the use case is well-defined, earning a 4 rather than a 5.

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