pay_tab_topup

Add more USDC to an open tab. Only the agent (tab opener) can top up.\n\n

SERVERPay Mcp SOURCE@pay-skill/mcp

Critical RISK CLASS

Category Financial

Parameters 00 required

Recommended Approval-gatedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-pay-skill-pay-mcp/pay-tab-topup.md

WHAT IT DOES

What pay_tab_topup does on Pay Mcp

AI agents use pay_tab_topup to commit financial operations through Pay Mcp, usually the final step of a payment, billing, or trading workflow. A call moves real money.

RISK

Why pay_tab_topup is rated Critical

This tool commits financial obligations by adding cryptocurrency funds to a tab account. Although restricted to the tab opener, it still represents a direct transfer of monetary value and can incur financial consequences. Misuse by an AI agent could drain funds or commit unintended payments. The constraint that 'only the agent can top up' mitigates some risk but does not eliminate the financial impact category.

From the tool's definition Tool description states 'Add more USDC to an open tab' — USDC is a stablecoin representing real monetary value on the Base blockchain.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pay_tab_topup safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Pay Mcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pay_tab_topup, this is the rule to start with:

pay_tab_topup Approval-gated

Any call to pay_tab_topup is blocked until a human approves it. The rest of the server keeps working.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pay_tab_topup": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

GATE THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Pay Mcp, apply this rule, and every pay_tab_topup call is checked against it from then on.

FAQ

Questions about pay_tab_topup

What does the pay_tab_topup tool do? +

Add more USDC to an open tab. Only the agent (tab opener) can top up.\n\n. It is categorised as a Financial tool in the Pay Mcp MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on pay_tab_topup? +

Register the Pay MCP server in PolicyLayer and add a rule for pay_tab_topup: 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 Pay Mcp. Nothing to install.

What risk level is pay_tab_topup? +

pay_tab_topup is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit pay_tab_topup? +

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

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

pay_tab_topup is provided by the Pay MCP server (@pay-skill/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Pay, and thousands of servers like it.

This server

All 15 Pay tools → Critical-risk tools on this server →

Across the catalogue

pay_invoice on Bitcoin MCP Server → All critical-risk MCP tools → The MCP Attack Database →

Guides

Govern MCP payment tools →Human-in-the-loop →Tool call approval →