AI agents call get_contact_by_id to retrieve information from Mcp Whatsapp Web without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves contact information by identifier. Retrieval operations that query existing data without modifying, deleting, or executing external logic are classified as Read. The severity is low because exposure of contact details alone does not enable destructive or financial harm, though information disclosure could be a privacy concern in some contexts.
From the tool's definition Tool description states 'Get contact details by JID' — a retrieval operation with no modification or side effects. Sibling tools (list_chats, list_messages, get_message_by_id) confirm this server is read-heavy for WhatsApp data.
Documented attack patterns abuse exactly the kind of access get_contact_by_id gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Whatsapp Web, and nothing reaches the server without passing your rules. This is the rule we recommend for get_contact_by_id:
{
"version": "1",
"default": "deny",
"tools": {
"get_contact_by_id": {}
}
}get_contact_by_id is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get contact details by JID. It is categorised as a Read tool in the Mcp Whatsapp Web MCP Server, which means it retrieves data without modifying state.
Register the Mcp Whatsapp Web MCP server in PolicyLayer and add a rule for get_contact_by_id: 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 Mcp Whatsapp Web. Nothing to install.
get_contact_by_id is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_contact_by_id 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.
Set action: deny in the PolicyLayer policy for get_contact_by_id. 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.
get_contact_by_id is provided by the Mcp Whatsapp Web MCP server (mario-andreschak/mcp-whatsapp-web). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Whatsapp Web, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
16 Mcp Whatsapp Web tools catalogued and risk-classified — across an index of 43,000+ MCP servers.