myob_invoice_prepare_update · MYOB Codex MCP: Risk & Policy

WHAT IT DOES

What myob_invoice_prepare_update does on MYOB Codex MCP

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

WHY IT NEEDS A POLICY

Why myob_invoice_prepare_update needs a policy

The tool modifies (updates) a sales invoice, which is reversible data mutation. While it involves financial documents, it does not directly move money or create financial obligations—it prepares changes requiring explicit approval. This is Write rather than Financial.

From the tool's definition Tool name contains 'update' and description states 'Prepare update of a sales invoice. Requires approval before commit.' This indicates modification of existing financial documents.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

myob_invoice_prepare_update Rate-limited

myob_invoice_prepare_update 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": {
    "myob_invoice_prepare_update": {
      "limits": [
        {
          "counter": "myob_invoice_prepare_update_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 MYOB Codex MCP, so you can run agents against it safely.

FAQ

Questions about myob_invoice_prepare_update

What does the myob_invoice_prepare_update tool do? +

Prepare update of a sales invoice. Requires approval before commit. It is categorised as a Write tool in the MYOB Codex 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 myob_invoice_prepare_update? +

Register the MYOB Codex MCP server in PolicyLayer and add a rule for myob_invoice_prepare_update: 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 MYOB Codex MCP. Nothing to install.

What risk level is myob_invoice_prepare_update? +

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

Can I rate-limit myob_invoice_prepare_update? +

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

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

myob_invoice_prepare_update is provided by the MYOB Codex MCP server (jaeko44/myob-codex-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.