send_flow_message · Whatsapp MCP: Risk & Policy

WHAT IT DOES

What send_flow_message does on Whatsapp

AI agents invoke send_flow_message to trigger actions in Whatsapp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why send_flow_message needs a policy

This tool sends an interactive flow/form message to an external user via WhatsApp, triggering an external communication operation. It is not a simple data write — it executes an outbound message delivery to a real user, potentially at scale. Misuse could result in spamming users with unwanted interactive forms.

From the tool's definition Send a WhatsApp Flow to a user. The user sees an interactive form/survey directly in the chat.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_flow_message Rate-limited

send_flow_message stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_flow_message": {
      "limits": [
        {
          "counter": "send_flow_message_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about send_flow_message

What does the send_flow_message tool do? +

Send a WhatsApp Flow to a user. The user sees an interactive form/survey directly in the chat. It is categorised as a Execute tool in the Whatsapp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on send_flow_message? +

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

What risk level is send_flow_message? +

send_flow_message is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit send_flow_message? +

Yes. Add a rate_limit block to the send_flow_message 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 send_flow_message completely? +

Set action: deny in the PolicyLayer policy for send_flow_message. 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 send_flow_message? +

send_flow_message is provided by the Whatsapp MCP server (spirit122/whatsapp-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.