build_image

What build_image does on Docker

AI agents invoke build_image to trigger actions in Docker. 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 build_image is rated High

This tool executes code (via Dockerfile instructions) whose effects depend on the Dockerfile contents provided as an argument. While not immediately destructive in the filesystem sense, it can run arbitrary commands, install packages, and trigger external operations during the build process. This places it in the Execute category with high severity due to the potential for code injection and resource consumption.

From the tool's definition Tool name is 'build_image' with description 'Build a Docker image from a Dockerfile'. Building Docker images executes arbitrary code defined in a Dockerfile (RUN commands, shell scripts, etc.) in a containerized environment.

The rule that runs build_image safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Docker, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For build_image, this is the rule to start with:

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

Questions about build_image