get_exchange_rate

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

No annotations are provided, so the description carries the burden. It discloses that quotes are only available on business days and that returns are PTAX buy/sell rates, which is useful behavioral context. However, it doesn't explain what happens on non-business days (empty response? error?) or whether there are rate limits or auth requirements, which a read-only economic-data tool with zero annotation coverage could reasonably disclose.

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 compact paragraphs with zero fluff. Front-loaded with purpose, then behavioral detail. Efficient and to the point. Minor deduction only because it omits any mention of what happens for non-business days, which could have been a short clarifying note.

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?

An output schema exists, so return structure doesn't need explanation. Parameters are fully covered at 100% schema coverage. Business-day constraint is disclosed. For a straightforward read-only lookup tool with two simple params, this is reasonably complete. It could note handling of invalid dates or unavailable quotes, but the core usage is covered.

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 description coverage is 100% and both parameters are well-documented in the schema (date format YYYY-MM-DD with business-day note, currency symbol example). The description adds marginal value by implying the date must be a business day, but this is already present in the schema. Per rubric, baseline 3 is appropriate when schema carries the load.

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?

Clear verb+resource ('Get the buy/sell exchange rate of a currency on a specific date'). It specifies it returns PTAX rates (buy/sell), which adds specificity. It doesn't explicitly differentiate from siblings like get_rate or list_rates, but the purpose is clear enough that the agent can likely distinguish them.

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 and schema both emphasize that quotes are only available on business days, and the date parameter description reinforces 'Use a business day; weekends and holidays have no quote.' This is clear context on when to use the tool. It doesn't explicitly name alternatives or exclusions, but the business-day constraint is actionable guidance.

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