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

Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond annotations: it returns the latest observed value per rate type across daily and monthly frequencies, requires no authentication, and cites the SDMX IR dataflow and open licence. No contradiction with 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?

The description is four sentences totaling around 60 words, with the primary action front-loaded. Every sentence earns its place: rate types, frequency behavior, policy context, authentication, and data provenance/licensing. No filler or redundancy.

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 simple read-only tool with one optional parameter, rich annotations, and an output schema, the description is complete. It covers what data is returned, the data source, licensing, and authentication requirements. Nothing needed to invoke the tool correctly 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?

Schema description coverage is 100% and the single optional parameter include_annual is already well-described in the schema, so the baseline is 3. The tool description does not add parameter-specific semantics beyond what the schema provides, which is acceptable given the high coverage.

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 and resource: 'Get the current key policy interest rates set by Norges Bank' and enumerates the exact rate types (key policy rate, overnight lending rate, reserve rate). It clearly distinguishes itself from sibling norgesbank.rates.history by emphasizing 'current' and 'latest observed value'.

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 establishes clear usage context: this is for the current/latest snapshot of rates, not historical data. It also notes 'No authentication required', which removes a potential barrier. However, it does not explicitly name alternatives like norgesbank.rates.history for historical queries, so it stops short of full when-not-to-use guidance.

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