currency_convert

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

With no annotations, the description carries full burden and discloses important behavior: Decimal precision, fallback to static rates on network failure with a warning, the meaning of the live parameter, and the return fields (converted amount, cross-rate, provider, timestamps).

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 structured into a clear summary, supported currencies, rate behavior, and an Args section. Each sentence adds useful information, and the document is front-loaded with the core purpose.

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?

The tool has five parameters and no annotations, but the description covers all behaviors, fallbacks, and output fields, and even notes the return format despite an output schema being present. It is fully complete for agent invocation.

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 lacks descriptions, but the description provides thorough explanations for all five parameters, including constraints (amount >= 0), types (ISO 4217 codes), and options for date and live. This gives agents everything needed to invoke the tool correctly.

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 and resource: 'Convert an amount between major currencies with Decimal precision.' It lists supported currencies and return fields, clearly distinguishing this from sibling financial tools like calculate_metric or loan_amortization.

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 explains default static rate behavior and when to use live/historical rates via date or live=true, providing clear context. It does not explicitly compare to alternatives, but the tool's unique conversion purpose makes usage self-evident.

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