# buy_topup

Purchase a top-up data package for an existing eSIM. Returns a Stripe checkout URL.

Agent View of the PolicyLayer registry record for `buy_topup`. HTML page: https://policylayer.com/tools/com-gitsim-chat/buy-topup

## Facts

- Tool: `buy_topup`
- Server: Gitsim Chat (`https://chat.gitsim.com/api/mcp`) — https://policylayer.com/tools/com-gitsim-chat.md
- Homepage: https://github.com/https://chat.gitsim.com/api/mcp
- Risk category: Financial (Critical risk)
- Registry record: grade C, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 3 (3 required)
- Recommended policy verdict: Approval-gated

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `iccid` | string | yes | The ICCID of the eSIM to top up |
| `session_key` | string | yes | Session key from a previous tool call |
| `package_code` | string | yes | The package code from search_topup_packages results |

Parameters from the server's own tool schema.

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

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "buy_topup",
    "arguments": {
      "iccid": "<iccid>",
      "session_key": "<session_key>",
      "package_code": "<package_code>"
    }
  }
}
```

## Why buy_topup is rated Critical

This tool explicitly purchases a data package and initiates a Stripe checkout, committing real financial obligations. It falls squarely in the Financial category, which is the most severe. Misuse by an AI agent could result in unauthorized purchases and financial losses.

From the tool's own definition: "'Purchase a top-up data package' and 'Returns a Stripe checkout URL' — directly initiates a financial transaction via Stripe payment processing."

## Use case

AI agents use buy_topup to commit financial operations through Gitsim Chat, 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 Gitsim Chat:

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

## Other tools on Gitsim Chat (8)

- `create_order` — Financial — https://policylayer.com/tools/com-gitsim-chat/create-order.md
- `check_data_balance` — Read — https://policylayer.com/tools/com-gitsim-chat/check-data-balance.md
- `check_order_status` — Read — https://policylayer.com/tools/com-gitsim-chat/check-order-status.md
- `get_business_context` — Read — https://policylayer.com/tools/com-gitsim-chat/get-business-context.md
- `get_package` — Read — https://policylayer.com/tools/com-gitsim-chat/get-package.md
- `list_esims` — Read — https://policylayer.com/tools/com-gitsim-chat/list-esims.md
- `search_packages` — Read — https://policylayer.com/tools/com-gitsim-chat/search-packages.md
- `search_topup_packages` — Read — https://policylayer.com/tools/com-gitsim-chat/search-topup-packages.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=com-gitsim-chat · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-gitsim-chat