Get cardholder-level balance data. Includes individual cardholder balances,
AI agents call get_activity_balances to retrieve information from Marqeta DiVA API MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a query/fetch operation to retrieve financial balance information. While it accesses sensitive financial data, it is a read-only operation that does not create, modify, delete, or execute actions. The severity is low because viewing balance data alone does not enable direct financial transactions or destructive operations.
From the tool's definition Tool name 'get_activity_balances' and description 'Get cardholder-level balance data. Includes individual cardholder balances' indicate a retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
Get cardholder-level balance data. Includes individual cardholder balances,. It is categorised as a Read tool in the Marqeta DiVA API MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Marqeta DiVA API MCP Server MCP server in PolicyLayer and add a rule for get_activity_balances: 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 Marqeta DiVA API MCP Server. Nothing to install.
get_activity_balances 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_activity_balances 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_activity_balances. 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_activity_balances is provided by the Marqeta DiVA API MCP Server MCP server (zvika-finally/marqeta-diva-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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