Get exchange rates

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

With no annotations, the description carries the full disclosure burden. It tells us the tool returns combined upstream and custom rates, which is useful context. However, it does not explicitly state whether this is a read-only operation (though 'Return' suggests it), whether it makes external network calls, or how it handles failures. This is a partial disclosure but lacks explicit reassurance about side effects.

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 a single, focused sentence: 'Return latest upstream and user-custom exchange rates.' It is front-loaded with the verb and object, and every word adds value with no redundancy.

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 simplicity of a zero-parameter getter, the description covers the main purpose. It does not specify the output format (e.g., whether results are keyed by currency or array of objects), and there's no output schema to fill the gap. Still, it is sufficient for most use cases, so a small deduction for lack of return structure detail.

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 input schema has zero parameters and schema description coverage is trivially 100%. With no parameters to describe, the baseline of 4 applies. The description adds nothing extra about parameters because there are none.

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 the specific verb 'Return' and identifies the resource as 'exchange rates', further clarifying it returns both 'upstream and user-custom' rates. This distinguishes it from sibling 'manage_custom_exchange_rate' which modifies rates rather than returning 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 implies the tool is used to retrieve exchange rates, but provides no explicit guidance on when to choose this over alternatives like 'manage_custom_exchange_rate' or how it relates to other financial data tools. There is no mention of any conditions or exclusions, so usage is only implied.

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