run_tflint · Terraform Best Practices MCP: Risk & Policy

WHAT IT DOES

What run_tflint does on Terraform Best Practices

AI agents invoke run_tflint to trigger actions in Terraform Best Practices. 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 run_tflint needs a policy

This tool triggers execution of an external linter process on user-supplied Terraform code. While tflint itself is read-only in intent (analyzing, not modifying infrastructure), the act of executing external programs falls squarely into Execute category. An AI agent could misuse this by running tflint on malicious or unexpected directory paths, accessing sensitive files, or chaining results into destructive actions.

From the tool's definition Tool runs tflint (a Terraform linter) against a directory, which executes an external tool with side effects including code analysis, rule checking, and potential system operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

run_tflint Rate-limited

run_tflint 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": {
    "run_tflint": {
      "limits": [
        {
          "counter": "run_tflint_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 Terraform Best Practices, so you can run agents against it safely.

FAQ

Questions about run_tflint

What does the run_tflint tool do? +

Run tflint against a Terraform project directory. It is categorised as a Execute tool in the Terraform Best Practices MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on run_tflint? +

Register the Terraform Best Practices MCP server in PolicyLayer and add a rule for run_tflint: 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 Best Practices. Nothing to install.

What risk level is run_tflint? +

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

Can I rate-limit run_tflint? +

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

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

run_tflint is provided by the Terraform Best Practices MCP server (@downatthebottomofthemolehole/terraform-best-practices-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.