set_default_currency · Rebillia MCP Server MCP

WHAT IT DOES

What set_default_currency does on Rebillia MCP Server

AI agents use set_default_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 set_default_currency needs a policy

This tool modifies company-level billing configuration (default currency setting) and may create new currency records. While the operation is technically reversible (a new default can be set), it affects critical billing infrastructure for an e-commerce merchant and could have downstream impacts on invoice generation, pricing, and reporting.

From the tool's definition "Set the company default currency. POST /currencies/default" - modifies company-level configuration. "Creates company currency if needed" - creates data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_default_currency Rate-limited

set_default_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": {
    "set_default_currency": {
      "limits": [
        {
          "counter": "set_default_currency_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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 set_default_currency

What does the set_default_currency tool do? +

Set the company default currency. POST /currencies/default. Required: currencyId (global currency ID). Creates company currency if needed. Fails if there are invoices with that currency. 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 set_default_currency? +

Register the Rebillia MCP Server MCP server in PolicyLayer and add a rule for set_default_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 set_default_currency? +

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

Can I rate-limit set_default_currency? +

Yes. Add a rate_limit block to the set_default_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 set_default_currency completely? +

Set action: deny in the PolicyLayer policy for set_default_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 set_default_currency? +

set_default_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.