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 that results are 'current' and sourced from BWO/SNB, which is useful context, but it does not go further into limitations, rate update behavior, or currency scope beyond the schema.

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 a single, tightly written sentence that immediately states the two supported data types. No filler or redundant explanation is present.

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 presence of a full input schema, an output schema, and comprehensive annotations, the description is sufficiently complete for ordinary use. A small gap is that it does not clarify what happens when 'currency' is omitted for exchange_rate, but the schema and output schema likely cover that.

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%, with all three parameters already explained. The description mostly restates the kind options and does not add meaningful details beyond the schema, so the baseline of 3 is appropriate.

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 clearly identifies the tool as providing 'current mortgage reference interest rate for rents (BWO) or SNB CHF exchange rates', which names the two concrete data resources. It does not use an explicit verb like 'retrieve', but the meaning is unambiguous and distinct from the sibling tools.

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: an agent should call this tool when asked for the BWO mortgage reference rate or SNB CHF exchange rates. However, it does not explicitly state when not to use it or name alternatives, so the guidance relies on inference rather than direct direction.

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