# exchangerate_historical

Get historical exchange rates for a specific date. Requires an API key.

Agent View of the PolicyLayer registry record for `exchangerate_historical`. HTML page: https://policylayer.com/tools/io-github-malamutemayhem-unclick-mcp-server/exchangerate-historical

## Facts

- Tool: `exchangerate_historical`
- Server: UnClick (`@unclick/mcp-server`) — https://policylayer.com/tools/io-github-malamutemayhem-unclick-mcp-server.md
- Install: `npx -y @unclick/mcp-server`
- Homepage: https://github.com/malamutemayhem/unclick-agent-native-endpoints.git
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 5 (3 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `day` | string | yes | Day number (1-31) |
| `base` | string | no | Base currency code (default USD) |
| `year` | string | yes | 4-digit year |
| `month` | string | yes | Month number (1-12) |
| `api_key` | string | no | ExchangeRate-API key (required) |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "exchangerate_historical",
    "arguments": {
      "day": "<day>",
      "year": "<year>",
      "month": "<month>"
    }
  }
}
```

## Why exchangerate_historical is rated Low

This tool retrieves historical financial data (exchange rates) but does not execute trades, move money, modify data, or trigger irreversible actions. It is purely informational and read-only, making it a Read category tool with low severity—misuse would only result in data retrieval, not financial loss or system damage.

From the tool's own definition: "Tool name 'exchangerate_historical' and description 'Get historical exchange rates for a specific date' indicate a query/retrieval operation with no side effects."

Risk signals: Handles credentials or secrets (api_key)

## Use case

AI agents call exchangerate_historical to retrieve information from UnClick without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches UnClick:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "exchangerate_historical": {}
  }
}
```

## Other tools on UnClick (1661)

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- `convex_hull_3d` — Execute — https://policylayer.com/tools/io-github-malamutemayhem-unclick-mcp-server/convex-hull-3d.md
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- …and 1631 more: https://policylayer.com/tools/io-github-malamutemayhem-unclick-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-malamutemayhem-unclick-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-malamutemayhem-unclick-mcp-server