start_container · Docker MCP Server MCP: Risk & Policy

WHAT IT DOES

What start_container does on Docker MCP Server

AI agents invoke start_container to trigger actions in Docker MCP Server. 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 start_container needs a policy

Starting a container triggers execution of potentially complex, arbitrary code defined in the container image. While not immediately destructive, this action initiates processes that can read/write data, access networks, consume resources, and interact with external systems—all of which depend on the container's contents and runtime environment.

From the tool's definition Tool name is 'start_container' and description states it will 'Start a Docker container'. Starting a container executes arbitrary workloads whose effects depend on the container's image and configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_container Rate-limited

start_container 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": {
    "start_container": {
      "limits": [
        {
          "counter": "start_container_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 Docker MCP Server, so you can run agents against it safely.

FAQ

Questions about start_container

What does the start_container tool do? +

Start a Docker container. It is categorised as a Execute tool in the Docker MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_container? +

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

What risk level is start_container? +

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

Can I rate-limit start_container? +

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

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

start_container is provided by the Docker MCP Server MCP server (pnmice/mcp-server-docker). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.