sw_get_currencies

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

The readOnlyHint annotation already establishes that this is a safe read operation. The description adds the detail that it returns both codes and units and that the currency_code is used for expense creation, but it doesn't disclose additional behavioral traits like return format or pagination. The annotation covers the safety profile, so this is adequate but not exceptional.

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 sentences: the first states the exact function, the second provides usage context. There is no filler or redundancy, making it highly concise and well-structured.

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 tool's simplicity (no parameters, no output schema, readOnly annotation), the description fully covers what the tool does and how to use the result. It mentions the returned data (codes and units) and gives a concrete application, making it complete for its complexity.

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, so there are no parameter semantics to explain. The schema is empty and fully self-descriptive. The description doesn't need to compensate, so the baseline score of 4 applies.

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 the specific verb 'Get' and clearly identifies the resource: Splitwise-supported currency codes and units. It is distinct from sibling tools that handle groups, users, expenses, etc., so the purpose is unambiguous.

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 provides actionable guidance: 'Use the currency_code value when creating expenses in non-default currencies.' This tells the agent when the retrieved data is relevant. It doesn't explicitly mention when not to use this tool or name alternatives, but there are no currency-specific siblings, so the context is clear.

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