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

With no annotations, the description carries the full burden and does disclose non-obvious traits: the data source (BIS), the sort order (highest first), and that each row includes the date of the latest value — which matters because policy rates change infrequently. It does not state update cadence or staleness, and read-only safety is only implied by 'current rates'.

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?

One sentence, front-loaded with the resource and scope, followed by source and sorting, then the filter hint. No filler and nothing buried.

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?

An output schema exists so return values need not be explained, and only one optional parameter is present. Coverage of scope, source, ordering and filtering makes it callable as-is; only the filter's accepted format and data freshness are left to inference.

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 0% (the single 'countries' parameter has no description, and its anyOf string/null shape is unexplained). The description partially compensates by revealing that currency codes are also accepted, but gives no format guidance — single value vs. comma-separated list, name vs. ISO code, and what happens if the filter matches nothing.

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 resource (current policy interest rates), scope (~40 central banks with named examples: Fed, ECB, BoE, BoJ, PBoC, SNB, RBI), and source (BIS). An agent can immediately tell this is a macro rate lookup and distinguish it from siblings like fx_rates or us_treasury_yields.

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?

Usage is implied by the resource itself (look up central bank policy rates), and 'Filter by country or currency code' hints at narrowing. But there is no explicit when-to-use vs alternatives such as fred_series (policy rate series) or fx_carry_ranking, and no statement of when the filter should be omitted to get the whole table.

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