Record a single transaction as a balanced double-entry. Money flows FROM one account TO another: for spending, from your bank/card to an expense account; for income, from an income account to your bank. Amounts are positive, in dollars.
AI agents use add_transaction to create or update resources in Bookie — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Bookie environment.
This tool creates new transaction records in a double-entry accounting system, making it a Write operation. However, it operates in a Financial context (moving money between accounts in a personal/business finance system).
From the tool's definition Tool description states it 'Record[s] a single transaction' and 'Money flows FROM one account TO another,' indicating creation and modification of financial records.
Attacks that exploit this kind of access
Record a single transaction as a balanced double-entry. Money flows FROM one account TO another: for spending, from your bank/card to an expense account; for income, from an income account to your bank. Amounts are positive, in dollars. It is categorised as a Write tool in the Bookie MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Bookie MCP server in PolicyLayer and add a rule for add_transaction: 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 Bookie. Nothing to install.
add_transaction is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_transaction 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 add_transaction. 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.
add_transaction is provided by the Bookie MCP server (yuens1002/bookie). 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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