AllRatesToday MCP Server

List supported currencies

list_currencies

Read-only

Retrieves supported ISO 4217 fiat currency codes, names, and symbols so you can validate user input and prevent errors before requesting exchange rates.

Instructions

Call this BEFORE other tools when you are unsure whether a currency code is supported, or when the user asks 'what currencies do you support?', 'is X a valid currency?', or 'what is the symbol for X?'. Returns { currencies: [{ code: 'USD', name: 'US Dollar', symbol: '$' }, ...], count } covering 160+ ISO 4217 fiat currencies. Does NOT include cryptocurrencies. Cheap to call (cached 24h upstream) — use it to validate user input and prevent downstream errors in get_exchange_rate / get_rates_authenticated / get_historical_rates.

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`count`	Yes
`currencies`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv0.7.9Oct 19, 2026

addedInput schema / $schema

Added value: +"http://json-schema.org/draft-07/schema#"

removedInput schema / additionalProperties
```
Removed value: -false
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "count": {
+      "type": "number"
+    },
+    "currencies": {
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "code": {
+            "type": "string"
+          },
+          "name": {
+            "type": "string"
+          },
+          "symbol": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "code",
+          "name",
+          "symbol"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "currencies",
+    "count"
+  ],
+  "type": "object"
+}

First observedv0.2.0Apr 21, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Annotations already declare readOnlyHint and openWorldHint, and the description adds real context beyond them: upstream caching for 24h, low call cost, the validation-purpose rationale, and the crypto exclusion. These are operational traits an agent needs for budgeting calls and setting expectations that annotations cannot express.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The directive that matters most — call this before other tools — is front-loaded, followed by concrete trigger phrases, then the return shape, scope limits, and cost. Every sentence carries a distinct piece of information with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the description need not detail return values, yet it still sketches the shape ({currencies: [{code,name,symbol}], count}). Given the zero-parameter simplicity and existing annotations, 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.

Parameters4/5

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 no parameter semantics to add, and the description correctly says nothing about inputs.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List supported currencies') and pins down scope precisely: 160+ ISO 4217 fiat currencies, explicitly excluding cryptocurrencies. An agent can distinguish this reference/enumeration tool from the rate-fetching siblings (get_exchange_rate, get_historical_rates) without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit temporal instruction ('Call this BEFORE other tools'), enumerates the exact user phrasings that should trigger it, and names the downstream tools it protects (get_exchange_rate / get_rates_authenticated / get_historical_rates). The when-not case (cryptocurrencies) is also stated.

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

Deploy Server