xero_create_invoice · Xero Expenses MCP: Risk & Policy

WHAT IT DOES

What xero_create_invoice does on Xero Expenses MCP

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

WHY IT NEEDS A POLICY

Why xero_create_invoice needs a policy

This tool creates new accounting documents (invoices) that represent financial obligations and revenue records. While not immediately moving money (which would be Financial category), creating invoices commits financial records and affects accounts receivable. This is a Write operation (creates reversible data) rather than Execute or Destructive, as invoices can be modified or deleted.

From the tool's definition Tool name 'xero_create_invoice' and description explicitly state 'Create a sales invoice' which creates new financial records in Xero accounting software.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

xero_create_invoice Rate-limited

xero_create_invoice 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": {
    "xero_create_invoice": {
      "limits": [
        {
          "counter": "xero_create_invoice_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 Xero Expenses MCP, so you can run agents against it safely.

FAQ

Questions about xero_create_invoice

What does the xero_create_invoice tool do? +

Create a sales invoice (accounts receivable) in Xero - use for invoices you send to customers. It is categorised as a Write tool in the Xero Expenses MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on xero_create_invoice? +

Register the Xero Expenses MCP server in PolicyLayer and add a rule for xero_create_invoice: 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 Xero Expenses MCP. Nothing to install.

What risk level is xero_create_invoice? +

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

Can I rate-limit xero_create_invoice? +

Yes. Add a rate_limit block to the xero_create_invoice 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 xero_create_invoice completely? +

Set action: deny in the PolicyLayer policy for xero_create_invoice. 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 xero_create_invoice? +

xero_create_invoice is provided by the Xero Expenses MCP server (muness/xero-expenses-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.