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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only says rates are 'live' and does not explain base currency, data source, behavior for invalid or empty q values, or what happens when the tool is called with no parameters.

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 efficient sentence with no filler. The 'FX Rates:' prefix is mildly redundant with the tool title, but the useful constraint 'for a currency code' is front-loaded. Under-specification is more a completeness problem than a conciseness problem.

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 single-parameter lookup with an output schema present, the description is at the edge of adequacy: it names the resource and the input type. Still, with no annotations and no details on valid currency-code formats or default behavior when q is empty, an agent cannot be fully confident in selecting and invoking the tool.

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 schema provides only a bare 'q' string with 0% description coverage, and the description adds the essential meaning that q is a currency code. However, it does not specify the expected format, casing, or whether the code is a base or quote currency.

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 identifies a concrete resource ('FX rates') and the key input ('a currency code'), clearly signaling a live exchange-rate lookup. The verb 'get' is implied rather than explicit, and it does not explicitly distinguish this from finance/crypto siblings like cryptoprice or coininfo, so it falls just short of a 5.

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?

There is no guidance about when to use this tool as opposed to the many finance, crypto, or country-related siblings in the list. The phrase 'for a currency code' hints at intended use, but no exclusions, prerequisites, or alternatives are mentioned.

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