wave_approve_invoice · Waveapps MCP: Risk & Policy

WHAT IT DOES

What wave_approve_invoice does on Waveapps

AI agents use wave_approve_invoice to create or update resources in Waveapps — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Waveapps environment.

WHY IT NEEDS A POLICY

Why wave_approve_invoice needs a policy

Approving an invoice is a Write operation because it modifies existing financial data (invoice status) reversibly—the approval can typically be undone by returning to draft status. It is not Destructive (data remains and can be reverted), not Financial (no money movement), and not Execute (no arbitrary code execution).

From the tool's definition Tool name 'wave_approve_invoice' and description indicate it changes invoice status from draft to approved, which is a state modification of financial records.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

wave_approve_invoice Rate-limited

wave_approve_invoice 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "wave_approve_invoice": {
      "limits": [
        {
          "counter": "wave_approve_invoice_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Waveapps, so you can run agents against it safely.

FAQ

Questions about wave_approve_invoice

What does the wave_approve_invoice tool do? +

Approves a draft invoice (status. It is categorised as a Write tool in the Waveapps MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on wave_approve_invoice? +

Register the Waveapps MCP server in PolicyLayer and add a rule for wave_approve_invoice: 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 Waveapps. Nothing to install.

What risk level is wave_approve_invoice? +

wave_approve_invoice is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit wave_approve_invoice? +

Yes. Add a rate_limit block to the wave_approve_invoice 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.

How do I block wave_approve_invoice completely? +

Set action: deny in the PolicyLayer policy for wave_approve_invoice. 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.

What MCP server provides wave_approve_invoice? +

wave_approve_invoice is provided by the Waveapps MCP server (lunaparker/waveapps-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.