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

Annotations already establish read-only, non-destructive, idempotent behavior, so the description's safety burden is low. It adds useful data semantics such as narrow/broad baskets, real vs nominal adjustment, and index base period, but does not disclose additional operational behavior like pagination or result limits. 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 concise and front-loaded: the first sentence states the action and resource, and the following sentences add meaningful distinctions without filler. Every sentence earns its place.

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?

Given the rich input schema with 100% parameter coverage, enums, defaults, and an output schema, the description provides enough conceptual and operational context for an agent to select and invoke the tool correctly. The series code, basket definitions, and competitiveness use case round out the definition.

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?

All six parameters are fully documented in the schema with descriptions, enums, defaults, and format examples, so the description does not need to repeat parameter details. The description adds conceptual context around EER and basket composition, but the schema already carries the parameter semantics.

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: 'Fetch a country's nominal or real effective exchange rate (EER) index from the BIS monthly EER series (WS_EER).' It clearly distinguishes this from simpler bilateral FX tools by explaining it is trade-weighted and useful 'beyond a single bilateral FX rate.'

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 last sentence gives clear usage context: 'Useful for gauging currency competitiveness beyond a single bilateral FX rate.' This implies when to choose this tool over a plain FX-rate tool, but it does not explicitly name alternatives or state when not to use it.

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