# check_balance

Check remaining balance and status of a card.

Agent View of the PolicyLayer registry record for `check_balance`. HTML page: https://policylayer.com/tools/agentpay/check-balance

## Facts

- Tool: `check_balance`
- Server: Agentpay (`agentpay-mcp-server`) — https://policylayer.com/tools/agentpay.md
- Install: `npx -y agentpay-mcp-server`
- Homepage: git+https://github.com/sagebhardt/agentpay.git
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 1 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `card_id` | string | yes | Card ID |

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": "check_balance",
    "arguments": {
      "card_id": "<card_id>"
    }
  }
}
```

## Why check_balance is rated Low

This tool queries the current state of a card's balance and status. It has no side effects, does not modify data, and does not commit financial transactions. While it accesses financial data, the action itself is purely informational. The broader server context (Agentpay payment tools) suggests financial operations, but this specific tool is a read operation.

From the tool's own definition: "Tool name 'check_balance' and description 'Check remaining balance and status of a card' indicate a read-only operation that retrieves card balance and status information without modifying or moving funds."

## Use case

AI agents call check_balance to retrieve information from Agentpay without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Agentpay:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "check_balance": {}
  }
}
```

## Other tools on Agentpay (16)

- `close_card` — Destructive — https://policylayer.com/tools/agentpay/close-card.md
- `revoke_api_key` — Destructive — https://policylayer.com/tools/agentpay/revoke-api-key.md
- `fill_card` — Execute — https://policylayer.com/tools/agentpay/fill-card.md
- `create_card` — Financial — https://policylayer.com/tools/agentpay/create-card.md
- `pay_checkout` — Financial — https://policylayer.com/tools/agentpay/pay-checkout.md
- `pay_merchant_clp` — Financial — https://policylayer.com/tools/agentpay/pay-merchant-clp.md
- `pay_person_clp` — Financial — https://policylayer.com/tools/agentpay/pay-person-clp.md
- `check_account` — Read — https://policylayer.com/tools/agentpay/check-account.md
- `detect_checkout` — Read — https://policylayer.com/tools/agentpay/detect-checkout.md
- `get_card_details` — Read — https://policylayer.com/tools/agentpay/get-card-details.md
- `list_api_keys` — Read — https://policylayer.com/tools/agentpay/list-api-keys.md
- `list_recipients` — Read — https://policylayer.com/tools/agentpay/list-recipients.md
- `list_transactions` — Read — https://policylayer.com/tools/agentpay/list-transactions.md
- `agentpay_signup` — Write — https://policylayer.com/tools/agentpay/agentpay-signup.md
- `create_api_key` — Write — https://policylayer.com/tools/agentpay/create-api-key.md
- `save_recipient` — Write — https://policylayer.com/tools/agentpay/save-recipient.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=agentpay · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/agentpay