Retrieve commonly used currencies and the number of countries using each, ordered by usage, to compare global currency adoption.
Get the most commonly used currencies and how many countries use them.
Returns:
List of currencies with usage counts, ordered by popularity
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It does disclose output semantics ('ordered by popularity') which is genuinely useful, but says nothing about read-only safety, result size, or pagination limits for a tool that could return many rows.
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?
Front-loaded one-sentence purpose followed by a compact Returns block; every line earns its place. Minor redundancy since the ordering information is restated where a separate output schema already exists, but it stays tight.
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 no-arg aggregation tool with an output schema, this is nearly complete: purpose, content, and ordering are all covered. It could be stronger by noting the default result size or that this is an unfiltered global aggregate.
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 the baseline is 4. There is nothing for the description to clarify beyond the fact that no filtering input is accepted, which is consistent with the empty schema.
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 the most commonly used currencies') plus the key payload detail ('how many countries use them'). It is clearly distinct from the nearest sibling, get_countries_by_currency, which maps the opposite direction, though it never names that sibling explicitly.
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 zero-parameter, read-only nature makes the use case largely self-evident, so usage is implied rather than stated. However, it gives no explicit when-to-use cue and does not point to get_countries_by_currency for callers who instead want countries filtered by a currency.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.