supported_currenciesList the currency codes InvoiceGen accepts for invoices (USD, EUR, INR, GBP, AED, SGD, AUD, CAD). Use before create_invoice when unsure whether a currency is supported. No exchange rates or currency conversion are provided.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| currencies | Yes | Supported upper-case currency codes. |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "currencies": {
+ "description": "Supported upper-case currency codes.",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "currencies"
+ ],
+ "type": "object"
+}Output schema / (root)Previous value: -{
- "properties": {
- "results": {
- "description": "List of supported currencies entries.",
- "items": {
- "properties": {
- "currencyCode": {
- "description": "The ISO 4217 currency code.",
- "type": "string"
- },
- "currencyName": {
- "description": "The full name of the currency.",
- "type": "string"
- },
- "currencySymbol": {
- "description": "The symbol used to represent the currency.",
- "type": "string"
- },
- "decimalPlaces": {
- "description": "The number of decimal places used by the currency.",
- "type": "integer"
- }
- },
- "required": [
- "currencyCode",
- "currencySymbol",
- "currencyName",
- "decimalPlaces"
- ],
- "type": "object"
- },
- "type": "array"
- }
- },
- "required": [
- "results"
- ],
- "type": "object"
-}New value: +nullOutput schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "results": {
+ "description": "List of supported currencies entries.",
+ "items": {
+ "properties": {
+ "currencyCode": {
+ "description": "The ISO 4217 currency code.",
+ "type": "string"
+ },
+ "currencyName": {
+ "description": "The full name of the currency.",
+ "type": "string"
+ },
+ "currencySymbol": {
+ "description": "The symbol used to represent the currency.",
+ "type": "string"
+ },
+ "decimalPlaces": {
+ "description": "The number of decimal places used by the currency.",
+ "type": "integer"
+ }
+ },
+ "required": [
+ "currencyCode",
+ "currencySymbol",
+ "currencyName",
+ "decimalPlaces"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "results"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds a valuable scope boundary: no exchange rates or conversion are provided, preventing a false expectation about the tool's capability.
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?
Three short sentences, front-loaded with the resource and its values, followed by usage guidance and then the scope limitation. No filler.
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?
An output schema exists, so return format needn't be explained; the description instead supplies the value set, the invocation context, and the limitation. Nothing an agent needs to call this correctly is missing.
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 per the rubric the baseline is 4. There is nothing for the description to clarify beyond confirming the parameterless nature of the call.
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 ('list the currency codes InvoiceGen accepts') and even enumerates the accepted values, so the agent knows exactly what comes back. It is trivially distinguishable from calculate_totals, create_invoice, and render_invoice_text.
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?
Explicitly says when to call it ('Use before create_invoice when unsure whether a currency is supported'), naming the sibling that motivates the call. The when-not condition is implied by 'when unsure', which is sufficient routing guidance for a static lookup.
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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