set_blocking · Mcp Pihole MCP: Risk & Policy

WHAT IT DOES

What set_blocking does on Mcp Pihole

AI agents invoke set_blocking to trigger actions in Mcp Pihole. 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.

WHY IT NEEDS A POLICY

Why set_blocking needs a policy

This tool toggles DNS blocking on/off for the entire Pi-hole system. Disabling DNS blocking would affect all clients on the network, removing malware/ad protection for every device. This is an external operational change with significant network-wide impact, making it Execute at high severity — an AI agent disabling blocking could expose the entire network to previously blocked threats.

From the tool's definition Enable or disable DNS blocking

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_blocking Rate-limited

set_blocking 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_blocking": {
      "limits": [
        {
          "counter": "set_blocking_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mcp Pihole, so you can run agents against it safely.

FAQ

Questions about set_blocking

What does the set_blocking tool do? +

Enable or disable DNS blocking. It is categorised as a Execute tool in the Mcp Pihole MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on set_blocking? +

Register the Mcp Pihole MCP server in PolicyLayer and add a rule for set_blocking: 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 Pihole. Nothing to install.

What risk level is set_blocking? +

set_blocking is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit set_blocking? +

Yes. Add a rate_limit block to the set_blocking 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_blocking completely? +

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

set_blocking is provided by the Mcp Pihole MCP server (obrien-matthew/mcp-pihole). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.