Convert currencies with official reference rates

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

Annotations already carry readOnlyHint=true, idempotentHint=true, and destrructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the two-regime rate regime, temporal coverage ('any date since 1999'), and the promise that output states method and citations explicitly. No contradiction with the 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?

Three sentences with zero waste: the main operation and sources are front-loaded, the output behavior (explicit method/citations) earns its sentence, and the date-format instruction is placed last where it reads as a takeaway. Every sentence adds information; nothing is repeated from the schema or title.

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?

With no output schema, the description carries the return-value burden and addresses it by stating the conversion result includes explicit method and citations. It covers what, which sources, which currencies, which dates, and how to format dates. Minor gaps remain around edge cases (unsupported codes, weekend dates for ECB) but nothing an agent needs for correct invocation is missing.

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?

While schema coverage is 75%, the description adds meaning the schema lacks: it maps from/to ISO codes into two concrete currency classes (the ~30 ECB majors vs the ~90 World Bank currencies like BBD, XCD, JMD, KES), and it clarifies the date parameter's dual format semantics and temporal reach. The 'amount' parameter remains implicitly defined (the number to convert), which is a minor gap at this coverage level.

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+resource ('Convert an amount between currencies') and goes further by naming the two official rate sources (ECB daily, World Bank annual-average). It is immediately distinguishable from siblings like inflation_adjust (inflation adjustment) and get_series/get_indicator (data retrieval), so an agent can tell what this tool uniquely does without opening the schema.

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 usable context: it tells the agent which date format to pass ('YYYY-MM-DD' for daily, 'YYYY' for annual-average) and ties each format to a currency class (~30 ECB majors vs ~90 World Bank currencies). It stops short of explicit exclusions or routing to alternatives such as inflation_adjust, but the invocation context is unambiguous.

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