Request a refund for a payment. Validates payment_id, amount (positive integer minor units), optional reason and currency. Returns a structured confirmation (stub).
Part of the Ui server.
Free to start. No card required.
AI agents use payments_refund to initiate financial transactions through Ui. Financial operations involve real money and are irreversible once processed. PolicyLayer blocks financial tools by default, requiring explicit human approval with transaction-level limits to prevent unauthorised spending.
payments_refund moves real money. Without a policy, an autonomous agent could initiate transactions that drain accounts or exceed budgets. PolicyLayer blocks financial tools by default, requiring human-in-the-loop approval with configurable spending limits per transaction and per time window.
Financial tools involve real money. Block by default and require explicit human approval before enabling.
{
"version": "1",
"default": "deny",
"tools": {
"payments_refund": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
}See the full Ui policy for all 38 tools.
These attack patterns abuse exactly the kind of access payments_refund gives an agent. Each links to the full case and the policy that stops it:
Other financial tools across the catalogue. The same approach applies to each: deny by default, or require human approval.
Request a refund for a payment. Validates payment_id, amount (positive integer minor units), optional reason and currency. Returns a structured confirmation (stub).. It is categorised as a Financial tool in the Ui MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Ui MCP server in PolicyLayer and add a rule for payments_refund: 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 Ui. Nothing to install.
payments_refund 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 payments_refund 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 payments_refund. 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.
payments_refund is provided by the Ui MCP server (@forgespace/ui-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 38 Ui tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.