exchange-rate.getLatestRates

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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so no additional safety disclosure is needed. The description adds no behavioral context beyond the annotations, and the phrase 'for a base currency' is slightly ambiguous given the empty input schema, though it is not contradicted by 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 one short sentence with no redundancy and puts the core verb and resource first. Every word 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 no-parameter read-only tool with an output schema and safety annotations, the description is nearly complete. The only notable gap is that it doesn't specify how the base currency is determined, especially since the input schema is empty.

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?

There are no parameters in the schema, so the baseline is 4. The description's mention of 'a base currency' adds conceptual meaning about the operation, even though there is no parameter to configure it.

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 uses a specific verb and resource ('Get latest exchange rates') and adds the scope 'for a base currency', which clearly distinguishes it from unrelated sibling tools. It is a minimal but unambiguous statement of what the operation returns.

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 conveys what data is returned, so an agent can infer when to call it, but it gives no explicit when-to-use guidance or exclusions and doesn't mention alternatives, even among the broader sibling set.

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