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

The readOnlyHint annotation already communicates that this is a safe read-only operation. The description adds useful context that the rates are 'indicative' and tied to Checkout.com's processes, but does not cover auth needs, rate limits, or response behavior beyond what annotations provide.

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 concise sentences, front-loaded with the tool's purpose, followed by a direct API endpoint reference. Every element earns its place with no wasted text.

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 read-only tool with full input schema coverage and annotations, the description is largely complete. The lack of an output schema means an agent might benefit from a note on return format, but the description does not need to explain return values here.

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%, so all four parameters are fully documented in the input schema. The description adds no additional parameter meaning, which matches the baseline of 3 when the schema does the heavy lifting.

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 the indicative foreign-exchange rates Checkout.com uses') with clear scope and an example use case. No sibling tool deals with forex rates, so it is easily distinguishable from the payment/customer/dispute tools.

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?

Usage is implied by the example '(e.g. for card payouts)', but there is no explicit guidance on when to use this tool versus alternatives or when not to use it. The unique nature of the resource makes the gap minor.

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