payee_create · Starling Bank MCP: Risk & Policy

WHAT IT DOES

What payee_create does on Starling Bank

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

WHY IT NEEDS A POLICY

Why payee_create needs a policy

This tool creates and stores a new payee record, which is a reversible modification (payees can typically be deleted or modified later). However, it sits within a financial account management system (Starling Bank) and could be misused to set up fraudulent payment recipients. While it doesn't directly move money, creating unauthorized payees is a precursor to unauthorized payments.

From the tool's definition Tool name 'payee_create' and description 'Create a new payee (person/company you can send payments to)' indicate data creation in a financial context. The tool modifies the user's payee list by adding a new payment recipient.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

payee_create Rate-limited

payee_create 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": {
    "payee_create": {
      "limits": [
        {
          "counter": "payee_create_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 Starling Bank, so you can run agents against it safely.

FAQ

Questions about payee_create

What does the payee_create tool do? +

Create a new payee (person/company you can send payments to). It is categorised as a Write tool in the Starling Bank MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on payee_create? +

Register the Starling Bank MCP server in PolicyLayer and add a rule for payee_create: 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 Starling Bank. Nothing to install.

What risk level is payee_create? +

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

Can I rate-limit payee_create? +

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

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

payee_create is provided by the Starling Bank MCP server (starling-bank-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.