Compute balances for accounts over a date range. Dates are ISO (YYYY-MM-DD). If you set only end_date, it
AI agents call balance to retrieve information from MCP Beancount Tool without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool reads and computes balance information from the ledger over a specified date range. It is a query/reporting operation with no write, execute, or destructive capability described. Severity is low as misuse only exposes financial summary data.
From the tool's definition 'Compute balances for accounts over a date range' — retrieves computed balance data, no side effects mentioned
Attacks that exploit this kind of access
Compute balances for accounts over a date range. Dates are ISO (YYYY-MM-DD). If you set only end_date, it. It is categorised as a Read tool in the MCP Beancount Tool MCP Server, which means it retrieves data without modifying state.
Register the MCP Beancount Tool MCP server in PolicyLayer and add a rule for 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 MCP Beancount Tool. Nothing to install.
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 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 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.
balance is provided by the MCP Beancount Tool MCP server (onesvat/mcp-beancount). 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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