set_custom_rate_limits · Whatsapp MCP: Risk & Policy

WHAT IT DOES

What set_custom_rate_limits does on Whatsapp

AI agents use set_custom_rate_limits 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 set_custom_rate_limits needs a policy

This tool modifies system configuration and rate-limiting policies, making it a Write operation that changes account settings. It is high severity because misconfiguration could enable spam, message flooding, or abuse of the WhatsApp messaging system, and affects account-wide policies rather than individual messages. It is not Execute/Destructive since the changes are reversible—rate limits can be reconfigured.

From the tool's definition Tool description states it can 'Override default rate limits with custom values. Set per-recipient limits, unique recipient caps, and message type restrictions.' This modifies account configuration settings.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_custom_rate_limits Rate-limited

set_custom_rate_limits 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": {
    "set_custom_rate_limits": {
      "limits": [
        {
          "counter": "set_custom_rate_limits_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 set_custom_rate_limits

What does the set_custom_rate_limits tool do? +

Enterprise only. Override default rate limits with custom values. Set per-recipient limits, unique recipient caps, and message type restrictions for your account. 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 set_custom_rate_limits? +

Register the Whatsapp MCP server in PolicyLayer and add a rule for set_custom_rate_limits: 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 set_custom_rate_limits? +

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

Can I rate-limit set_custom_rate_limits? +

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

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

set_custom_rate_limits 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.