AI agents call check_alive to retrieve information from MCP Recon without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Despite the empty description, the tool's name and server context indicate a probing/querying operation to determine if a host or service is accessible. This is consistent with Read-category reconnaissance—retrieving status information without side effects.
From the tool's definition Tool name 'check_alive' in a web security reconnaissance context; sibling tools are primarily passive/active information gathering (dns_records, ip_information, port_scan, detect_technologies, http_headers).
Documented attack patterns abuse exactly the kind of access check_alive gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Recon, and nothing reaches the server without passing your rules. This is the rule we recommend for check_alive:
{
"version": "1",
"default": "deny",
"tools": {
"check_alive": {}
}
}check_alive is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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check_alive. It is categorised as a Read tool in the MCP Recon MCP Server, which means it retrieves data without modifying state.
Register the MCP Recon MCP server in PolicyLayer and add a rule for check_alive: 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 Recon. Nothing to install.
check_alive 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 check_alive 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 check_alive. 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.
check_alive is provided by the MCP Recon MCP server (sundayz-hunter/mcp_recon). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Recon, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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13 MCP Recon tools catalogued and risk-classified — across an index of 43,000+ MCP servers.