get_fx_rate

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

Without annotations, the description carries the full transparency burden. It specifies the data source (ECB via Frankfurter) and uses the term 'live', which implies near real-time data. However, it does not disclose update frequency, rate limits, or any caching behavior. This is adequate for a read-only lookup tool but could be more explicit.

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 consists of two concise sentences. The first sentence states the core function and source. The second sentence provides use cases and a parameter format example. Every sentence adds value without redundancy or filler.

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 that an output schema exists, the description need not detail return values. It covers the source, usage, and parameter format. It misses details like error handling for invalid codes or rate limits, but for a simple lookup tool, it is sufficiently complete.

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 0% coverage, meaning no descriptions for parameters. The description compensates by explaining that 'symbols can be comma-separated, e.g. INR,EUR,GBP' and implies base defaults to USD. It adds meaning beyond the bare schema, though it could explicitly state the expected ISO currency codes.

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 clearly states that the tool provides 'live currency exchange rates' using 'ECB reference, via Frankfurter'. It explicitly mentions use cases like 'what's the USD/INR rate', converting amounts, or FX-impact questions, making the purpose unambiguous and distinct from sibling tools that focus on financial calculations rather than real-time rates.

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 gives clear scenarios for using the tool (currency conversion, FX-impact questions) but does not explicitly state when not to use it or mention alternatives among the extensive sibling list. While the context implies it's for live rates only, lacking explicit exclusions prevents a top score.

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