currency_history

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

Annotations already declare the tool read-only, idempotent, and non-destructive, so the bar is lower. The description adds the API key requirement and pandas DataFrame return type, but it also contradicts itself by saying 'Latest data' while supporting a specific date, muddling the actual behavior. It does not disclose rate limits, error handling, or data availability.

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 docstring-style block with a link and parameter documentation. It is reasonably concise but the structure is fragmented: the summary line is vague and the link to documentation could be relocated. The parameter section is useful but could be tightened.

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 4-parameter tool with no output schema, the description is insufficient. It fails to clarify that this is historical data (despite the name), describe the structure of the returned DataFrame, or differentiate from sibling tools like currency_latest and currency_time_series. The return type is mentioned but not the columns or frequency.

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 0% schema description coverage, the description carries the burden for parameters. It explains base, date (with example format), symbols, and api_key (including where to find it), which adds real meaning beyond the bare schema. However, it does not specify the format for symbols (e.g., comma-separated) or clarify whether api_key is mandatory, leaving some ambiguity.

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 says 'Latest data from currencyscoop.com' but the tool is named currency_history and accepts a date parameter, implying historical data. There is no specific verb like 'fetch' or 'retrieve', and it does not distinguish itself from siblings like currency_latest 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?

No guidance is provided on when to use this tool versus alternatives. The description does not explain whether this is for historical rates, current rates, or how it differs from currency_latest or currency_time_series, leaving the agent with no selection criteria.

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