send_image_message · Whatsapp MCP: Risk & Policy

WHAT IT DOES

What send_image_message does on Whatsapp

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

WHY IT NEEDS A POLICY

Why send_image_message needs a policy

The tool sends (creates) an image message to WhatsApp contacts. While the message itself is reversible in theory (can be deleted later), the send action is a write operation with observable side effects: it transmits data to recipients and creates persistent records. The blast radius is medium—a misused tool could spam users, send inappropriate images, or leak sensitive media to wrong recipients.

From the tool's definition Tool description states 'Send an image' which creates and transmits a message object. This is a write operation that modifies conversation state by adding a new message artifact.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_image_message Rate-limited

send_image_message 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": {
    "send_image_message": {
      "limits": [
        {
          "counter": "send_image_message_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 Whatsapp, so you can run agents against it safely.

FAQ

Questions about send_image_message

What does the send_image_message tool do? +

Send an image via URL or media ID. Supports caption. It is categorised as a Write tool in the Whatsapp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on send_image_message? +

Register the Whatsapp MCP server in PolicyLayer and add a rule for send_image_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_image_message? +

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

Can I rate-limit send_image_message? +

Yes. Add a rate_limit block to the send_image_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_image_message completely? +

Set action: deny in the PolicyLayer policy for send_image_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_image_message? +

send_image_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.