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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds a small detail about returning conversion rate and timestamp, but no deeper behavioral context (e.g., live vs. snapshot rates, data source, limits) is provided.

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, front-loaded pair of sentences with no redundant words. It communicates purpose and core output clearly, earning maximum points for conciseness.

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 simple read-only tool, the annotations and schema cover safety and parameter semantics well, and the output schema presumably documents return values. However, the description does not clarify whether passing 'amount' alters the return (e.g., converted amount vs. just rate), which introduces slight ambiguity.

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 100% description coverage for all three parameters, so the description does not need to add parameter meaning. It does not; it stays silent on parameter semantics, which is acceptable given the schema's completeness.

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 opens with a specific verb ('Convert') and identifies the resource ('between fiat currencies') with a concrete example ('USD to EUR'). This clearly differentiates it from the many crypto-focused sibling tools like get_crypto_price.

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 usage for fiat currency conversion but does not explicitly state when to use this tool over alternatives, nor does it mention any exclusions. The example clarifies fiat scope, but no alternative tools are referenced.

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