create_invoice · e-Fatura MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_invoice does on e-Fatura MCP Server

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

WHY IT NEEDS A POLICY

Why create_invoice needs a policy

The tool creates new invoices in an official government tax system (GİB e-Arşiv). While creation is reversible via the cancel_invoice sibling tool, this is a Write operation that generates binding financial/tax documents with potential legal and compliance implications. It does not move money directly (so not Financial), but creates records with significant downstream effects.

From the tool's definition Tool description states "Create a new e-Fatura invoice in the GIB system." The verb "Create" indicates data creation. The context of e-invoicing in an official Turkish Revenue Administration system means this creates legally binding financial documents.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_invoice Rate-limited

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": {
    "create_invoice": {
      "limits": [
        {
          "counter": "create_invoice_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

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

FAQ

Questions about create_invoice

What does the create_invoice tool do? +

Create a new e-Fatura invoice in the GIB system. It is categorised as a Write tool in the e-Fatura 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_invoice? +

Register the e-Fatura MCP Server MCP server in PolicyLayer and add a rule for 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 e-Fatura MCP Server. Nothing to install.

What risk level is create_invoice? +

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

Can I rate-limit create_invoice? +

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

Set action: deny in the PolicyLayer policy for 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 create_invoice? +

create_invoice is provided by the e-Fatura MCP Server MCP server (reyhansunduk/efatura-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.