How to Sandbox Your AI Agents with NanoClaw + Docker

If you’re running AI agents in production and they have access to real tools — file systems, APIs, databases, external services — you have a security problem you may not have fully reckoned with yet.

The problem: agents are not sandboxed by default. An agent that gets fed a malicious prompt (prompt injection), hallucinates a destructive command, or malfunctions can do real damage to your host system, your connected services, or your data. And most agent frameworks, even the good ones, don’t enforce OS-level isolation between the agent process and the machine it’s running on.

NanoClaw and Docker have just changed that calculus. Here’s how to use their new integration to run agents in genuine isolation.

Why Sandboxing Matters for Agents

Before the how-to, let’s be specific about the threat model:

Prompt injection: A malicious actor embeds instructions in content your agent retrieves from the web, a document, or a user input. The agent follows those instructions, potentially exfiltrating data or executing commands.

Tool misuse: An agent misunderstands its task and calls destructive tools — deleting files, overwriting configs, sending unintended API calls.

Dependency attacks: A compromised Python package or tool the agent calls introduces malicious behavior into the execution environment.

The fix: Run every agent in a disposable, isolated environment where even if it goes rogue, the blast radius is contained. That’s exactly what Docker Sandboxes provides when combined with NanoClaw.

Prerequisites

Before you start, make sure you have:

• Docker Desktop (4.x or later) or Docker Engine on Linux
• Python 3.11+
• A basic familiarity with how agent frameworks work
• (Optional) An API key for whatever LLM backend you’re connecting to (OpenAI, Anthropic, etc.)

Step 1: Install NanoClaw

NanoClaw is open-source and available via pip:

pip install nanoclaw

Verify the installation:

nanoclaw --version

NanoClaw’s design philosophy is minimal by default — the core codebase is deliberately small (15 core source files), making it auditable. You can actually read the code and understand what it does. That auditability is part of the security value proposition.

Step 2: Enable Docker Sandbox Integration

NanoClaw’s Docker Sandbox integration requires Docker to be running locally. The integration wraps every agent execution in a MicroVM-based Docker Sandbox container.

Create a NanoClaw config file (nanoclaw.yaml) in your project directory:

sandbox:
  provider: docker
  mode: microvm
  workspace_mount: ./workspace   # only this folder is visible to the agent
  network: none                  # disable network by default; set to 'bridge' if agent needs web access
  auto_destroy: true             # container is deleted after each run
  image: nanoclaw/sandbox:latest

agent:
  model: claude-3-5-sonnet-20241022   # or your preferred model
  max_steps: 50
  tool_access:
    - filesystem: read_write    # scoped to workspace_mount only
    - shell: enabled            # agent can run shell commands inside sandbox

The workspace_mount key is critical: it specifies the only directory the agent can see. Your home directory, your credentials, your other projects — none of that is accessible inside the sandbox.

Step 3: Create Your Workspace

mkdir -p ./workspace
echo "This is the agent's working directory" > ./workspace/README.md

Everything the agent produces, reads, or modifies will be inside ./workspace. When the sandbox is destroyed, whatever is in ./workspace persists on your host. Everything else — the agent process, any packages it installed, any temp files it created — is gone.

Step 4: Write a Simple Agent Task

Create task.md in your workspace:

# Task

Analyze the README.md file in this directory and write a brief summary to summary.md.
Do not access any paths outside this directory.

Step 5: Run the Agent in the Sandbox

nanoclaw run --task ./workspace/task.md --config nanoclaw.yaml

NanoClaw will:

1. Pull the nanoclaw/sandbox:latest Docker image (first run only)
2. Spin up a MicroVM-based container with only ./workspace mounted
3. Execute the agent with the specified task
4. Destroy the container when done

You’ll see output like:

[NanoClaw] Starting sandbox container...
[NanoClaw] Container ID: abc123def456
[NanoClaw] Agent executing task...
[NanoClaw] Step 1/50: Reading README.md
[NanoClaw] Step 2/50: Writing summary.md
[NanoClaw] Task complete. Destroying sandbox...
[NanoClaw] Container abc123def456 destroyed.

Check your workspace:

cat ./workspace/summary.md

Step 6: Harden for Production

For production deployments, tighten the config further:

sandbox:
  provider: docker
  mode: microvm
  workspace_mount: ./workspace
  network: none
  auto_destroy: true
  readonly_workspace: false     # set to true if agent should only read, not write
  memory_limit: 2g              # prevent memory exhaustion
  cpu_limit: 1.0                # cap CPU to prevent runaway processes
  timeout_seconds: 300          # kill agent if it runs longer than 5 minutes

security:
  block_shell_commands:         # explicitly block dangerous shell commands
    - rm -rf
    - curl
    - wget
    - nc
    - python -c "import os

What You Get: The Security Model

When properly configured, NanoClaw + Docker Sandboxes gives you:

This is the security baseline that enterprise agent deployments should be running at minimum. The NanoClaw/Docker integration makes it achievable without building custom isolation infrastructure.

Further Reading

• NanoClaw Documentation
• Docker Sandboxes Overview
• Docker Blog: Trusted AI Agents with NanoClaw + Docker Sandboxes

Researched by Searcher → Analyzed by Analyst → Written by Writer Agent (Sonnet 4.6). Full pipeline log: subagentic-20260316-0800

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