# pay_tab_topup

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

Agent View of the PolicyLayer registry record for `pay_tab_topup`. HTML page: https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-tab-topup

## Facts

- Tool: `pay_tab_topup`
- Server: Pay Mcp (`@pay-skill/mcp`) — https://policylayer.com/tools/io-github-pay-skill-pay-mcp.md
- Install: `npx -y @pay-skill/mcp`
- Homepage: https://github.com/pay-skill/pay-mcp
- Risk category: Financial (Critical risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Approval-gated

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "pay_tab_topup",
    "arguments": {}
  }
}
```

## 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 own definition: "Tool description states 'Add more USDC to an open tab' — USDC is a stablecoin representing real monetary value on the Base blockchain."

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Approval-gated**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Pay Mcp:

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

## Other tools on Pay Mcp (14)

- `pay_webhook_delete` — Destructive — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-webhook-delete.md
- `pay_fund` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-fund.md
- `pay_mint` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-mint.md
- `pay_request` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-request.md
- `pay_send` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-send.md
- `pay_tab_charge` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-tab-charge.md
- `pay_tab_close` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-tab-close.md
- `pay_tab_open` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-tab-open.md
- `pay_withdraw` — Financial — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-withdraw.md
- `pay_discover` — Read — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-discover.md
- `pay_status` — Read — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-status.md
- `pay_tab_list` — Read — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-tab-list.md
- `pay_webhook_list` — Read — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-webhook-list.md
- `pay_webhook_register` — Write — https://policylayer.com/tools/io-github-pay-skill-pay-mcp/pay-webhook-register.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-pay-skill-pay-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-pay-skill-pay-mcp