FX Timeseries

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description's only added behavioral fact is the ~1-year range ceiling, which is already repeated in the schema's 'start' description, so marginal new context; no rate limits, auth needs, or data-freshness caveats are disclosed.

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?

A single tight sentence with the core action and its scope front-loaded, followed by the input-format reminder. Nothing is wasted, though it is slightly dense and could split the format guidance.

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 an output schema present, return values need not be explained, and annotations carry the safety profile. The description covers scope, date format, range limit, and multi-target input, leaving only the sibling-routing question unanswered.

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 restates the YYYY-MM-DD format and that one or more target currencies are expected, but adds no syntax or constraint detail beyond what the schema already documents for start, end, base, and symbols.

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?

States a specific verb and resource ('Get a time series of exchange rates') plus scope (base currency, date range, max ~1 year) and a purpose hint (trend analysis). This is clear, but it never differentiates itself from near-siblings like fx_historical or fx_rates, which likely also return rate data over dates.

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?

'useful for trend analysis' implies the use case, but the description never says when to pick this over fx_historical, fx_rates, or fx_convert. Usage is inferable rather than stated, and no exclusions or prerequisites are given.

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