create_currency · Rebillia MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_currency does on Rebillia MCP Server

AI agents use create_currency to create or update resources in Rebillia MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Rebillia MCP Server environment.

WHY IT NEEDS A POLICY

Why create_currency needs a policy

This tool creates new currency records in the billing system, which is a reversible write operation. However, it merits medium severity because misconfiguration of currency conversion rates could cause billing errors, transaction disputes, or financial reconciliation issues across the e-commerce platform, even though the action itself can be corrected after creation.

From the tool's definition Tool creates a company currency via POST /currencies with parameters like currencyId, conversionRate, and fixedRate. The description explicitly states 'Create a company currency,' which is a data creation operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_currency Rate-limited

create_currency stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_currency": {
      "limits": [
        {
          "counter": "create_currency_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Rebillia MCP Server, so you can run agents against it safely.

FAQ

Questions about create_currency

What does the create_currency tool do? +

Create a company currency. POST /currencies. Required: currencyId (global currency ID), conversionRate (number), fixedRate (boolean). It is categorised as a Write tool in the Rebillia MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_currency? +

Register the Rebillia MCP Server MCP server in PolicyLayer and add a rule for create_currency: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Rebillia MCP Server. Nothing to install.

What risk level is create_currency? +

create_currency is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_currency? +

Yes. Add a rate_limit block to the create_currency rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block create_currency completely? +

Set action: deny in the PolicyLayer policy for create_currency. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides create_currency? +

create_currency is provided by the Rebillia MCP Server MCP server (rhinosaas/rebillia-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.