Return ISO 4217 currencies with code, name and minor units, filterable by query. Pure CPU, instant.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"q": "<q>"
},
"name": "currency_list"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| q | Yes | Filter by code or name |
Changes observed during successful MCP inspections.
Input schema / properties / qAdded value: +{
+ "description": "Filter by code or name",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "q"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations supplied, the description carries the burden and does add useful behavioral context: 'Pure CPU, instant' signals no external I/O or latency concern, and 'Return' implies a read operation. It does not explicitly state no side effects or unmatched-query behavior, but for a simple list tool the disclosure is mostly adequate.
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, front-loaded sentences with no filler. The returned fields and performance characteristic are stated efficiently.
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 one-parameter reference lookup with no output schema, the description names the returned fields (code, name, minor units), states filtering, and notes performance. An agent has enough information to call it correctly.
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 coverage is 100%, so the parameter's meaning is already fully documented as 'Filter by code or name'. The description only repeats that the tool is query-filterable and adds no syntax, matching behavior, or edge-case details beyond the schema, so the baseline 3 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?
States a specific verb and resource: 'Return ISO 4217 currencies' and names the returned fields. This is clearly a reference-data list operation, distinguishable from the conversion-oriented sibling convert_currency.
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 implies lookup/filter usage through 'filterable by query' and 'Pure CPU, instant', but does not explicitly say when to use this instead of convert_currency or country_list, nor 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.
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