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

Annotations already declare readOnlyHint=true, destructiveHint=false and closed-world scope, so safety is covered. The description adds genuinely useful behavior beyond that: the lookback window is warmed up on price history fetched before startDate, so values don't depend on the requested range's left edge — a non-obvious edge-case disclosure. It stops short of describing output shape or any rate limits.

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?

Three tight sentences, front-loaded with the definition of %K/%D, then interpretation, then the warm-up caveat. No filler and nothing buried.

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 single-ticker read-only indicator with full parameter coverage, the description covers definition, interpretation thresholds, and the warm-up edge case. With no output schema, a brief note on the returned series (columns, ordering) would make it fully self-sufficient, so it falls just short of complete.

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 every parameter including kPeriod, dPeriod and maxResults is already documented, setting the baseline at 3. The description's explanation of %K/%D maps loosely onto kPeriod and dPeriod but never names them or adds format details beyond the schema.

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?

Names a specific indicator and defines precisely what it computes: %K measures the close relative to the high/low range over the lookback window, and %D is the SMA of %K. It is self-defining against siblings like GetBollingerBands or GetAverageTrueRange, though it never explicitly says how it differs from those alternate technical indicators.

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?

Offers interpretive context ('useful for spotting overbought >80 and oversold <20 conditions') but gives no guidance on when to choose this indicator over the sibling technical-analysis tools, nor any prerequisites. Usage is implied by the overbought/oversold framing rather than stated as a selection rule.

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