FX rate time series

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds that data is daily and across a date range, but does not disclose traits like pagination, rate limits, or behavior when no data exists. It does not contradict annotations.

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?

Two sentences, zero waste. First sentence states the function concisely; second sentence provides a practical use case. Well-structured and efficient.

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 annotations and schema coverage, the description is mostly sufficient. It captures the core functionality, though it could mention that it returns a time series of rates for multiple currency pairs. The lack of an output schema is compensated by the clear purpose.

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 50%, with descriptions only for 'start' and 'end'. The description mentions 'across a date range,' which relates to these parameters. No additional meaning is provided for 'base' or 'symbols' beyond the schema fields. 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 clearly states 'Daily FX rates across a date range,' specifying the resource and scope. It distinguishes from sibling tools like fx_latest_rates and fx_open_rates by emphasizing the date range and use in charts/backtests, though it lacks an explicit verb and does not differentiate from fx_historical_rate.

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 offers a clear use case ('Use for currency charts and backtests'), implying when to use it. However, it does not specify when not to use it (e.g., if only the latest rate is needed) or mention alternatives among the many sibling FX tools.

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