hetzner · Coolify MCP: Risk & Policy

WHAT IT DOES

What hetzner does on Coolify

AI agents use hetzner to create or update resources in Coolify — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Coolify environment.

WHY IT NEEDS A POLICY

Why hetzner needs a policy

The tool both reads (list locations/server-types/images/ssh-keys) and writes (create server). Per the rules, the most severe applicable category wins. Creating a cloud server is a Write action with high severity because it provisions real infrastructure that incurs costs and consumes resources.

From the tool's definition 'create server' — the tool can provision new Hetzner cloud infrastructure, which creates billable resources and has operational impact

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

hetzner Rate-limited

hetzner 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "hetzner": {
      "limits": [
        {
          "counter": "hetzner_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about hetzner

What does the hetzner tool do? +

Manage Hetzner cloud resources: list locations/server-types/images/ssh-keys, create server. It is categorised as a Write tool in the Coolify MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on hetzner? +

Register the Coolify MCP server in PolicyLayer and add a rule for hetzner: 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 Coolify. Nothing to install.

What risk level is hetzner? +

hetzner is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit hetzner? +

Yes. Add a rate_limit block to the hetzner 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 hetzner completely? +

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

hetzner is provided by the Coolify MCP server (jurislm/coolify-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.