Add a new transaction (expense or income). Amount should be positive for income, negative for expenses. Use payee_name to specify who you paid or received from.
AI agents use add_transaction to create or update resources in Actual Budget MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Actual Budget MCP Server environment.
This tool creates new financial transaction records, which is a reversible write operation. It ranks below Destructive (which would be irreversible deletion) and Financial (which typically involves actual money movement like payments or transfers). However, it's more severe than a simple data read because it modifies the user's financial records.
From the tool's definition Tool description states it will 'Add a new transaction' which creates new data in the financial system. The tool accepts parameters to create expense or income entries, making it a write/create operation.
Attacks that exploit this kind of access
Add a new transaction (expense or income). Amount should be positive for income, negative for expenses. Use payee_name to specify who you paid or received from. It is categorised as a Write tool in the Actual Budget MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Actual Budget MCP Server 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 Actual Budget MCP Server. 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 Actual Budget MCP Server MCP server (yhc0712/actual-budget-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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