tf_untaint · Terraform MCP Server MCP: Risk & Policy

WHAT IT DOES

What tf_untaint does on Terraform MCP Server

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

WHY IT NEEDS A POLICY

Why tf_untaint needs a policy

tf_untaint modifies Terraform state by removing the taint mark from a resource, which changes how Terraform plans future operations (a tainted resource would otherwise be destroyed and recreated). This is a reversible state modification (the resource can be re-tainted), placing it in the Write category.

From the tool's definition "Remove taint from resource" — untainting modifies the state of a resource in Terraform's state file by clearing its tainted flag

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

tf_untaint Rate-limited

tf_untaint 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": {
    "tf_untaint": {
      "limits": [
        {
          "counter": "tf_untaint_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 Terraform MCP Server, so you can run agents against it safely.

FAQ

Questions about tf_untaint

What does the tf_untaint tool do? +

Remove taint from resource. It is categorised as a Write tool in the Terraform MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on tf_untaint? +

Register the Terraform MCP Server MCP server in PolicyLayer and add a rule for tf_untaint: 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 Terraform MCP Server. Nothing to install.

What risk level is tf_untaint? +

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

Can I rate-limit tf_untaint? +

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

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

tf_untaint is provided by the Terraform MCP Server MCP server (mjrestivo16/mcp-terraform). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.