AI agents use waha_unblock_contact to create or update resources in WAHA MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your WAHA MCP Server environment.
This tool modifies the blocked status of a contact, which is a reversible write operation (can be re-blocked if needed). It affects user relationships and communication permissions but does not delete data, execute code, or move money. Severity is medium because unblocking a contact could expose the user to unwanted communications if misused by an agent, but it remains reversible and non-destructive.
From the tool's definition Tool name 'waha_unblock_contact' and description 'Unblock a contact' indicate modification of contact blocking status, a reversible change to user settings/relationships.
Documented attack patterns abuse exactly the kind of access waha_unblock_contact gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and WAHA MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for waha_unblock_contact:
{
"version": "1",
"default": "deny",
"tools": {
"waha_unblock_contact": {
"limits": [
{
"counter": "waha_unblock_contact_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} waha_unblock_contact 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.
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Unblock a contact. It is categorised as a Write tool in the WAHA MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the WAHA MCP Server MCP server in PolicyLayer and add a rule for waha_unblock_contact: 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 MCP Server. Nothing to install.
waha_unblock_contact is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the waha_unblock_contact 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 waha_unblock_contact. 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.
waha_unblock_contact is provided by the WAHA MCP Server MCP server (seejux/waha-whatsapp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from WAHA MCP Server, 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.
52 WAHA MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.