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

With no annotations, the description carries the full behavioral burden. It discloses the averaging methodology, base-currency conversion order, the 1830-day maximum date span, and that the first and last periods are cut to the requested range. It does not cover authentication, rate limits, or error behavior, but for a read-only data endpoint it is quite transparent.

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 appropriately sized and front-loads the core averaging behavior before adding constraints. Every sentence adds useful information, though the second paragraph could be slightly tighter.

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 7-parameter tool with no output schema, the description explains the returned concept (period averages with low and high), the grouping period, base-currency semantics, and date-range limits. It does not fully enumerate the response shape, but it provides enough for correct 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?

Schema coverage is 100%, so the baseline is 3. The description still adds meaning beyond the schema by explaining that daily rates are first expressed against base_currency and then averaged, and by adding the maximum 1830-day span between date_from and date_to.

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 states a specific verb and resource: it averages daily rates per calendar period and reports each period's low and high. This is clearly distinct from sibling tools such as getConvert, getFluctuation, and getHistorical.

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 a meaningful use case by noting that average rates are what IFRS and US GAAP allow for translating income and expenses. However, it does not explicitly say when to choose this tool over alternatives like getFluctuation or getHistorical, nor does it list exclusions.

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