invoice_match
Three-way match an invoice against a list of purchase orders (amount %-diff + line-item similarity → best open PO, discrepancies, auto-approve verdict). Deterministic, no keys.
This record as markdown: /tools/com-wingmanprotocol-agent-gateway/invoice-match.md
What invoice_match does on Gateway
AI agents call invoice_match to retrieve information from Gateway without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
invoice | object | Yes | the invoice (vendor_name,total,line_items[],…) |
purchase_orders | array | — | candidate POs (po_number,status,received,total,line_items[]) |
Parameters from the server's own tool schema.
Why invoice_match is rated Low
invoice_match retrieves data, performs calculations on existing records (invoices and POs), and returns analytical results (best match, discrepancies, verdict). It reads and compares information but does not create, modify, delete, or execute external operations. This is a classic Read category tool—data retrieval and analysis without side effects.
From the tool's definition The tool performs matching and comparison operations: 'match an invoice against a list of purchase orders', 'amount %-diff + line-item similarity', 'discrepancies'. These are query and analysis activities with no modification of data indicated.
Attacks that exploit this kind of access
The rule that runs invoice_match safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Gateway, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For invoice_match, this is the rule to start with:
invoice_match is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Gateway, apply this rule, and every invoice_match call is checked against it from then on.
Questions about invoice_match
Three-way match an invoice against a list of purchase orders (amount %-diff + line-item similarity → best open PO, discrepancies, auto-approve verdict). Deterministic, no keys. It is categorised as a Read tool in the Gateway MCP Server, which means it retrieves data without modifying state.
invoice_match accepts 2 parameters: invoice, purchase_orders. Required: invoice. The full parameter table on this page comes from the server's own tool schema.
Register the Gateway MCP server in PolicyLayer and add a rule for invoice_match: 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 Gateway. Nothing to install.
invoice_match 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 invoice_match 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 invoice_match. 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.
invoice_match is provided by the Gateway MCP server (https://wingmanprotocol.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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