bnr_last_10_days

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

With no annotations, the description carries the full transparency burden. It discloses ordering, 'one entry per day,' and the same shape as bnr_latest_rates, but it does not clarify whether 'last 10 days' means calendar days or business days, whether today is included, or whether any rate-limit/auth considerations apply. 'Get' implies read-only, but the day-count ambiguity is a notable gap.

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 two focused sentences: the first states exactly what is returned and the second adds use-case context and distinguishes it from the heavyweight archive. No wasted words and the key facts are front-loaded.

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 zero-parameter tool with an output schema, this is nearly complete: the agent knows the time range, ordering, shape reference, and relationship to bnr_latest_rates. The only notable omission is the precise meaning of 'last 10 days' regarding business vs calendar days.

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 tool has zero parameters and 100% schema coverage, so the baseline is 4. The description appropriately contains no parameter-specific details because there are none to document.

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 uses a specific verb ('Get') and names the exact resource ('BNR's official exchange rates') with a clear time window ('each of the last 10 days') and ordering ('oldest first'). It also signals how it relates to siblings by saying it has the same shape as bnr_latest_rates, making it distinct from the per-year archive.

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?

It explicitly states when this tool is useful: 'short-term trend questions without hitting the per-year archive.' However, it never explicitly contrasts it with bnr_latest_rates for the single-latest-rate case, so the agent must infer that boundary.

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