AI agents invoke run_grep to trigger actions in Pentester-MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool name suggests running grep, which executes a search/pattern-matching command. However, in a pentesting context with arbitrary command execution capabilities and Docker sandboxing, grep could be used to search sensitive files or exfiltrate data. The description is empty, lowering confidence. Severity is high given the server's purpose of running penetration testing tools autonomously.
From the tool's definition Tool name 'run_grep' on a penetration testing MCP server that 'autonomously execute[s] over 200 open-source penetration testing tools'; description is empty.
Documented attack patterns abuse exactly the kind of access run_grep gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Pentester-MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for run_grep:
{
"version": "1",
"default": "deny",
"tools": {
"run_grep": {
"limits": [
{
"counter": "run_grep_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}run_grep stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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run_grep. It is categorised as a Execute tool in the Pentester-MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Pentester- MCP server in PolicyLayer and add a rule for run_grep: 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 Pentester-MCP. Nothing to install.
run_grep is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the run_grep 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 run_grep. 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.
run_grep is provided by the Pentester- MCP server (halilkirazkaya/pentester-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Pentester-MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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337 Pentester-MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.