AI agents call get_payment to retrieve information from Cardzero without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves payment status information without modifying, creating, or destroying data. The phrase 'Check the status' indicates a read-only query. Although the broader server manages financial instruments (USDC, wallets), this specific tool only inspects existing state.
From the tool's definition Tool name is 'get_payment' and description states 'Check the status of a specific payment by its ID' — a query operation with no side effects.
Attacks that exploit this kind of access
Check the status of a specific payment by its ID. No authentication required. It is categorised as a Read tool in the Cardzero MCP Server, which means it retrieves data without modifying state.
Register the Cardzero MCP server in PolicyLayer and add a rule for get_payment: 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 Cardzero. Nothing to install.
get_payment 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 get_payment 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 get_payment. 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.
get_payment is provided by the Cardzero MCP server (mrocker/cardzero-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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