myob_oauth_exchange_code · MYOB Codex MCP: Risk & Policy

WHAT IT DOES

What myob_oauth_exchange_code does on MYOB Codex MCP

AI agents use myob_oauth_exchange_code 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_oauth_exchange_code needs a policy

This tool performs an OAuth token exchange and persists the resulting tokens along with a businessId. It creates/saves new authentication state, which is a Write operation. The severity is high because misuse could allow an attacker to hijack an authenticated MYOB session by exchanging a stolen OAuth code, gaining full access to financial accounting data and all mutating operations on the server.

From the tool's definition 'exchange an OAuth code for MYOB tokens and save businessId context' — stores/saves credential tokens and business context

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

myob_oauth_exchange_code Rate-limited

myob_oauth_exchange_code 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_oauth_exchange_code": {
      "limits": [
        {
          "counter": "myob_oauth_exchange_code_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_oauth_exchange_code

What does the myob_oauth_exchange_code tool do? +

Manually exchange an OAuth code for MYOB tokens and save businessId context. 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_oauth_exchange_code? +

Register the MYOB Codex MCP server in PolicyLayer and add a rule for myob_oauth_exchange_code: 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_oauth_exchange_code? +

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

Can I rate-limit myob_oauth_exchange_code? +

Yes. Add a rate_limit block to the myob_oauth_exchange_code 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_oauth_exchange_code completely? +

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

myob_oauth_exchange_code 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.