check_balance
Check remaining balance and status of a card.
This record as markdown: /tools/agentpay/check-balance.md
What check_balance does on Agentpay
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.
| Parameter | Type | Required | Description |
|---|---|---|---|
card_id | string | Yes | Card ID |
Parameters from the server's own tool schema.
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 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.
Attacks that exploit this kind of access
The rule that runs check_balance safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Agentpay, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For check_balance, this is the rule to start with:
check_balance is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Agentpay, apply this rule, and every check_balance call is checked against it from then on.
Questions about check_balance
Check remaining balance and status of a card. It is categorised as a Read tool in the Agentpay MCP Server, which means it retrieves data without modifying state.
check_balance accepts 1 parameter: card_id. Required: card_id. The full parameter table on this page comes from the server's own tool schema.
Register the Agentpay MCP server in PolicyLayer and add a rule for check_balance: 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 Agentpay. Nothing to install.
check_balance is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the check_balance 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 check_balance. 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.
check_balance is provided by the Agentpay MCP server (agentpay-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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