whatsapp_send_text · Waha MCP: Risk & Policy

WHAT IT DOES

What whatsapp_send_text does on Waha

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

WHY IT NEEDS A POLICY

Why whatsapp_send_text needs a policy

This tool creates new data (messages) in a reversible manner—messages can be deleted via whatsapp_delete_message and conversations can be undone. It is Write rather than Execute because it performs a straightforward data creation action (sending a message) rather than triggering arbitrary external operations.

From the tool's definition Tool sends text messages to contacts and groups via WhatsApp API. Description states 'Send a text message to a contact (person or group)' with arguments for contactId and message text, creating new messages that modify the state of conversations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

whatsapp_send_text Rate-limited

whatsapp_send_text 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": {
    "whatsapp_send_text": {
      "limits": [
        {
          "counter": "whatsapp_send_text_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about whatsapp_send_text

What does the whatsapp_send_text tool do? +

Send a text message to a contact (person or group). CORE tier supports text messages only (no images, video, audio, or documents). A rate limit delay is enforced between sends to avoid WhatsApp detection. Args: - contactId: ${CONTACT_ID_DESC} - text: Message text to send - replyTo: Optional message ID to quote-reply to (get from whatsapp_read_messages) Returns: - status:. It is categorised as a Write tool in the Waha MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on whatsapp_send_text? +

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

What risk level is whatsapp_send_text? +

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

Can I rate-limit whatsapp_send_text? +

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

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

whatsapp_send_text is provided by the Waha MCP server (@marcos-heidemann/waha-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.