sw_get_currencies

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that this returns reference data (codes and units) and how the result is consumed downstream, but says nothing about caching, stability of the list, or the exact response shape. Adequate but not rich.

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?

Two short sentences, zero filler. The purpose is front-loaded and the usage note follows immediately, so an agent can act after the first clause.

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 zero-parameter, read-only reference lookup with no output schema, the description covers what is returned (currency codes and units) and why it matters. The only minor gap is that the exact response structure isn't described, but that is low stakes for a static list.

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 takes zero parameters, so there is no parameter semantics to document and the baseline is 4. The description correctly does not invent parameter behavior; it instead explains the output value's downstream use.

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 verb and resource ('Get all Splitwise-supported currency codes and units') and precisely names what is returned. No sibling tool deals with currency data, so it is trivially distinguishable from the rest of the sw_* set.

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?

Gives clear context for use: 'Use the currency_code value when creating expenses in non-default currencies,' which ties this lookup to the expense-creation workflow. It stops short of naming sw_create_expense explicitly or stating when not to call it, but the usage condition is unambiguous.

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