create_scheduled_transaction · Ynab MCP: Risk & Policy

WHAT IT DOES

What create_scheduled_transaction does on Ynab

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

WHY IT NEEDS A POLICY

Why create_scheduled_transaction needs a policy

This tool creates a new scheduled/recurring financial transaction in YNAB. While it doesn't immediately move money, it commits future financial obligations that will recur automatically. It is a Write operation (creates data reversibly — the scheduled transaction can be deleted), but given it's on a financial management platform and schedules future money movements, severity is high.

From the tool's definition Create a new scheduled (recurring) transaction. Date must be in the future (up to 5 years).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_scheduled_transaction Rate-limited

create_scheduled_transaction 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_scheduled_transaction": {
      "limits": [
        {
          "counter": "create_scheduled_transaction_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 Ynab, so you can run agents against it safely.

FAQ

Questions about create_scheduled_transaction

What does the create_scheduled_transaction tool do? +

[1 API call] Create a new scheduled (recurring) transaction. Date must be in the future (up to 5 years). It is categorised as a Write tool in the Ynab 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_scheduled_transaction? +

Register the Ynab MCP server in PolicyLayer and add a rule for create_scheduled_transaction: 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 Ynab. Nothing to install.

What risk level is create_scheduled_transaction? +

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

Can I rate-limit create_scheduled_transaction? +

Yes. Add a rate_limit block to the create_scheduled_transaction 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_scheduled_transaction completely? +

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

create_scheduled_transaction is provided by the Ynab MCP server (justmytwospence/ynab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.