ucp_checkout_create
AI agents use ucp_checkout_create to commit financial operations through Ucp — usually the final step of a payment, billing, or trading workflow. A call moves real money.
The tool name strongly suggests initiating a checkout process in a shopping/payment context. Given the server's explicit purpose of facilitating purchases and payments, creating a checkout is a financial action that begins a transaction flow.
From the tool's definition Tool name 'ucp_checkout_create' on a server described as enabling AI assistants to 'shop at UCP-enabled merchants' with tools for 'checkout' and 'payment'; sibling tools include 'ucp_checkout_complete' which likely finalizes payment.
Documented attack patterns abuse exactly the kind of access ucp_checkout_create gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Ucp, and nothing reaches the server without passing your rules. This is the rule we recommend for ucp_checkout_create:
{
"version": "1",
"default": "deny",
"tools": {
"ucp_checkout_create": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
}Any call to ucp_checkout_create is blocked until a human approves it. The rest of the server keeps working.
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ucp_checkout_create. It is categorised as a Financial tool in the Ucp MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Ucp MCP server in PolicyLayer and add a rule for ucp_checkout_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 Ucp. Nothing to install.
ucp_checkout_create is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the ucp_checkout_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.
Set action: deny in the PolicyLayer policy for ucp_checkout_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.
ucp_checkout_create is provided by the Ucp MCP server (nguthrie/ucp-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Ucp, 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.
5 Ucp tools catalogued and risk-classified — across an index of 43,000+ MCP servers.