Create an expense in Wave from receipt data. Vendor is optional - expenses can be created without vendor association and vendors can be added later.
AI agents use create_expense_from_receipt to create or update resources in Wave Accounting MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Wave Accounting MCP Server environment.
This tool creates (writes) expense records in an accounting system. While it modifies financial data, it is reversible (expenses can be edited or deleted later) and does not commit financial obligations or move money directly, distinguishing it from Financial category.
From the tool's definition Tool description states 'Create an expense in Wave from receipt data' — the verb 'Create' indicates a reversible write operation that modifies financial records by adding an expense entry.
Documented attack patterns abuse exactly the kind of access create_expense_from_receipt gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Wave Accounting MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_expense_from_receipt:
{
"version": "1",
"default": "deny",
"tools": {
"create_expense_from_receipt": {
"limits": [
{
"counter": "create_expense_from_receipt_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_expense_from_receipt stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create an expense in Wave from receipt data. Vendor is optional - expenses can be created without vendor association and vendors can be added later. It is categorised as a Write tool in the Wave Accounting MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Wave Accounting MCP Server MCP server in PolicyLayer and add a rule for create_expense_from_receipt: 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 Wave Accounting MCP Server. Nothing to install.
create_expense_from_receipt 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 create_expense_from_receipt 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 create_expense_from_receipt. 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.
create_expense_from_receipt is provided by the Wave Accounting MCP Server MCP server (vinnividivicci/wave_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Wave Accounting MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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9 Wave Accounting MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.