Assign a budgeted amount to a category or move money between categories for a specific month. This is the primary tool for allocating funds.
AI agents use manage-budgeted-amount to create or update resources in You Need A Budget (YNAB) MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your You Need A Budget (YNAB) MCP environment.
This tool modifies budgeting data by assigning amounts and reallocating funds between categories. While it affects financial planning, it does not directly move money out of accounts or create financial obligations—it only changes budget allocations, which are reversible modifications. This makes it Write rather than Financial or Execute.
From the tool's definition Tool description states: 'Assign a budgeted amount to a category or move money between categories for a specific month.' These are budget allocation operations that modify financial data reversibly.
Documented attack patterns abuse exactly the kind of access manage-budgeted-amount gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and You Need A Budget (YNAB) MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for manage-budgeted-amount:
{
"version": "1",
"default": "deny",
"tools": {
"manage-budgeted-amount": {
"limits": [
{
"counter": "manage-budgeted-amount_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}manage-budgeted-amount 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.
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Assign a budgeted amount to a category or move money between categories for a specific month. This is the primary tool for allocating funds. It is categorised as a Write tool in the You Need A Budget (YNAB) MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the You Need A Budget (YNAB) MCP server in PolicyLayer and add a rule for manage-budgeted-amount: 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 You Need A Budget (YNAB) MCP. Nothing to install.
manage-budgeted-amount is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the manage-budgeted-amount 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.
Set action: deny in the PolicyLayer policy for manage-budgeted-amount. 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.
manage-budgeted-amount is provided by the You Need A Budget (YNAB) MCP server (jtewen/ynab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from You Need A Budget (YNAB) MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
14 You Need A Budget (YNAB) MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.