Exchange Rate

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

Annotations already cover read-only/idempotent/non-destructive behavior, and the description adds value by declaring the response structure and currency coverage. It goes beyond the schema's one generic parameter. Minor extra context like base-currency semantics or list size would be helpful but is not essential given the 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?

The description is two short sentences with no filler. The verb and resource are front-loaded, and the return shape follows immediately. Every sentence contributes useful information.

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?

With no output schema, the description takes on the burden of explaining the response, and it does so by naming the fields and example currencies. Some ambiguity remains about how the rate is quoted (e.g., base currency) and whether the list is exhaustive, but the tool is simple and annotations cover the safety profile.

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?

The only parameter, _jq, is fully described in the input schema with detailed semantics and examples, so the description need not repeat it. The tool description doesn't elaborate on parameters, but baseline 3 is appropriate since schema coverage is 100%.

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 states a specific verb and resource ('Get exchange rates for all supported currencies') and includes the exact return shape (list of from_currency, to_currency, rate, timestamp). It does not explicitly name or differentiate from sibling tools, but the resource is unambiguous enough to distinguish it from the large sibling set.

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 given on when to use this tool versus alternatives such as quote, market_status, or now. The usage context is only implied ('for exchange rates'), with no mention of when not to use it or which sibling covers adjacent scenarios.

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