latest_rates

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

With no annotations, the description carries full behavioral burden and does disclose useful traits: one rate per requested currency or all tracked currencies when symbols is omitted, the presence of a rate_date, ECB working-day publication, and a note field for lagging currency feeds. It does not cover error behavior or authentication, but for a public reference-rate lookup the disclosed behavior is substantial.

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 front-loaded with the core resource and scope, then efficiently adds return-shape and publication caveats. Every sentence earns its place, with no redundant or filler language.

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 two-parameter lookup with an output schema and no annotations, the description supplies enough context to invoke the tool correctly. It explains the default scope when symbols is omitted and the working-day publication caveat, while the output schema handles detailed return structure.

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 the baseline is 3. The description adds only limited parameter context, reiterating that symbols omitted returns all currencies and that base is a single currency, both of which the schema already documents.

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 names the specific resource (latest published ECB reference rates) and scopes it to one base currency. It implicitly distinguishes itself from siblings like historical_rate and rate_timeseries by emphasizing 'latest published,' and from convert/list_currencies by describing a rate snapshot rather than conversion or currency enumeration.

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 intended use is implied by 'latest published' and the sibling set, but the description does not state when to use this tool instead of historical_rate, rate_timeseries, convert, or list_currencies. There are no explicit exclusions or alternative-routing instructions.

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