Currency Fluctuation

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds behavioral context by listing the exact return fields (startRate, endRate, absolute change, percent change) and noting that endDate defaults to yesterday. No contradictions.

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 concise sentences: first states purpose, second details return fields, third provides usage note. Front-loaded with key information, no wasted words.

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 read-only fluctuation retrieval tool with rich annotations and no output schema, the description effectively covers return fields and default behavior. It could mention error handling or format of numerical values, but it is largely complete given the tool's simplicity.

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?

With 100% schema coverage, the baseline is 3. The description mentions that startDate is required and endDate defaults to yesterday, which is already in the schema. It does not add new semantics beyond what the schema provides for parameters.

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 starts with a clear verb and resource: 'Retrieve exchange rate fluctuation metrics for currencies over a date range.' It specifies return fields (startRate, endRate, absolute change, percent change) which distinguishes it from sibling tools like currency_historical_rates or currency_time_series.

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 says 'Useful for volatility analysis and comparing currency movements,' implying a use case but does not explicitly state when to use this tool over alternatives like currency_time_series or currency_historical_rates. No exclusion or alternative guidance is provided.

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