Currency Latest Rates

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

The description discloses that the tool returns a dictionary mapping currency codes to rates relative to the base, and that filtering reduces response size. The annotations already cover read-only and idempotent behavior, so the description adds useful context about the return format and the effect of filtering, without contradicting annotations.

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 extremely concise—just two sentences—with the main action (retrieve latest rates) stated first, followed by output format and a key usage hint. Every sentence adds value, no unnecessary words.

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 tool with 3 parameters and no output schema, the description provides a clear picture of what the tool does and returns. It mentions the scope (170+ fiat, 830+ crypto) and the benefit of filtering. It does not explain the update frequency parameter, but that is detailed in the schema. Overall, it is sufficiently complete for 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?

All three parameters have descriptions in the schema (100% coverage), so the baseline is 3. The description adds the practical insight that filtering with 'symbols' reduces response size, which goes beyond the schema's statement and aids agent decision-making. The other parameters (base, updates) are adequately covered by the schema.

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 it retrieves the latest exchange rates for a vast set of currencies, distinguishing it from historical or fluctuation tools by emphasizing 'latest'. It also specifies the return format as a rates dictionary, which is distinct from sibling tools like currency_converter.

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 mentions filtering to reduce response size, but does not explicitly state when to use this tool versus alternatives like currency_historical_rates or currency_fluctuation. The usage context is implied but not thoroughly delineated.

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