Get historical commodity rates

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

No annotations are provided, so the description carries the full burden. It adds valuable behavioral context by disclosing the data availability start date (1990-01-01) and the fallback to the nearest date when the exact date has no rate. This goes beyond a simple 'returns rates' disclosure, though it does not detail response format or error handling.

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 with no fluff. Front-loaded with the core action ('Returns open/high/low/close rates'), then adds two key behavioral notes. Every sentence earns its place.

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 simple two-parameter tool with no output schema, the description covers the essential aspects: what it returns, which symbols/date, data availability, and the fallback behavior. The schema fills in parameter details, making this a complete description for the tool's complexity.

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 baseline is 3, but the description enriches the date parameter by explaining the date range and fallback behavior, adding meaning beyond the format-only schema. The symbols parameter is mentioned as 'one or more symbols' in the description, though the schema already covers comma-separated format.

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 the tool returns OHLC rates for symbols on a specific historical date, which is a specific verb+resource+scope. It distinguishes itself from siblings like get_latest_rates and get_time_series by emphasizing 'past date' and 'nearest available date' fallback.

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 provides clear context for when to use this tool (historical lookups on a specific date) and implicitly contrasts with "past date" vs. likely "latest" or "time series" siblings. However, it does not explicitly name alternatives or state when not to use it, which would earn a 5.

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