nono and containers

nono and containers (Docker, Podman, etc.) operate at different layers of isolation and complement each other well. Containers provide namespace and resource isolation; nono adds fine-grained, path-level filesystem control. You can use either on its own or combine them for defense in depth. This guide helps you understand what each brings to the table and when to use one, the other, or both.

Quick Comparison

Aspect	nono	Docker Container
Startup time	~0ms	~100-500ms
Setup required	None	Dockerfile, daemon
Filesystem model	Path-level allow/deny	Separate filesystem
Works on host files	Yes (directly)	Requires volume mounts
Credential protection	Automatic blocklist	Manual (don’t mount)
Network isolation	On/off	Full namespace
Resource limits	Memory cap (cgroup v2, Linux)	Yes (cgroups)
Process isolation	No	Yes (PID namespace)

What nono Adds

nono is strongest when you need:

Zero-Latency Startup

# Instant startup - no container overhead
nono run --allow-cwd -- claude-code

# Compare to Docker
docker run -v $(pwd):/work -it my-agent  # 100-500ms+ overhead per invocation

Direct Access to Your Working Directory

AI coding agents need to read and modify your actual source files. With nono, this works naturally:

# Agent can edit files in current directory
nono run --allow-cwd -- aider

With Docker, you need to configure volume mounts and handle permission issues:

# Volume mounts can cause UID/GID mismatches
docker run -v $(pwd):/work -u $(id -u):$(id -g) my-agent

Automatic Credential Protection

nono blocks sensitive paths by default, even if you allow a parent directory:

# Allows ~/projects but still blocks ~/.ssh, ~/.aws, etc.
nono run --allow ~/projects -- agent

With Docker, you must be careful not to mount sensitive directories:

# Easy to accidentally expose secrets
docker run -v $HOME:/home/user my-agent  # Dangerous!

Zero Configuration

nono requires no setup - just install and run:

brew install nono
nono run --allow-cwd -- my-agent

Docker requires:

Docker daemon running
Dockerfile for custom images
Understanding of volumes, networks, users
Image pulls and builds

What Containers Add

Containers cover areas that nono does not:

Full Environment Isolation

If the agent needs specific system libraries, language runtimes, or tools:

FROM python:3.11
RUN pip install numpy pandas tensorflow

nono runs in your existing environment - it doesn’t provide a separate runtime.

Resource Limits

Containers can limit CPU, memory, and I/O:

docker run --memory=2g --cpus=1 my-agent

nono can cap memory with --memory (a cgroup v2 hard ceiling on Linux; see Resource limits), so a runaway agent cannot exhaust host RAM. It does not yet limit CPU or I/O — for those, reach for a container.

Process Isolation

Containers have separate PID namespaces - processes inside can’t see or signal host processes:

# Inside container, can only see container processes
docker run my-agent ps aux  # Shows only container processes

nono shares the host PID namespace - the sandboxed process can see (but not necessarily interact with) other processes.

Reproducible Environments

For CI/CD or sharing exact environments:

# Same environment everywhere
docker run my-org/agent:v1.2.3 -- run-tests

Using Both Together

Because nono and containers operate at different layers, they combine naturally. The container handles namespace isolation and resource limits; nono handles path-level filesystem control and credential blocking inside the container:

# Dockerfile
FROM ubuntu:22.04
COPY --from=ghcr.io/always-further/nono:latest /usr/bin/nono /usr/bin/nono
RUN apt-get update && \
    apt-get install -y --no-install-recommends ca-certificates && \
    rm -rf /var/lib/apt/lists/*
ENTRYPOINT ["nono", "run", "--allow", "/work"]

# Defense in depth: container + nono
docker run -v $(pwd):/work my-nono-agent -- claude-code

This gives you:

Namespace isolation from the container — processes, network, and mounts are separated from the host
Resource limits from the container — cap CPU, memory, and I/O
Path-level control from nono — the agent can only touch /work, even though the container filesystem is larger
Credential blocking from nono — sensitive paths are denied automatically, even if a home directory is mounted in

Threat Model Comparison

What nono Protects Against

Reading/writing files outside allowed paths
Accessing credentials (~/.ssh, ~/.aws, etc.)
Running blocked commands (rm, dd, etc.)
Network access (when blocked)

What Containers Protect Against

All of the above (but with a fair amount of configuration)
Process visibility and signaling
Resource exhaustion (with limits)
Environment contamination

What Neither Protects Against

Kernel vulnerabilities
Side-channel attacks
Prompt Injection (which no one can fully prevent)
Social engineering (agent convinces you to run dangerous command)

Performance Comparison

Startup Time

# nono: instant
time nono run --allow-cwd -- echo hello
# real    0m0.005s

# Docker (warm, image cached)
time docker run alpine echo hello
# real    0m0.350s

# Docker (cold, needs pull)
time docker run alpine echo hello
# real    0m2.500s

Memory Overhead

nono: ~0 MB (just applies sandbox and execs)
Docker: ~10-50 MB per container (runtime overhead)

Disk Usage

nono: ~2 MB binary
Docker: 100 MB+ per image (varies widely)

Adding nono to an Existing Workflow

If you’re currently using Docker only for sandboxing (not for environment isolation), nono can simplify your setup:

# Before: Docker for sandboxing only
docker run -v $(pwd):/work -w /work python:3.11 python script.py

# After: nono (uses your installed Python, zero overhead)
nono run --allow-cwd -- python script.py

If you need Docker for environment reasons, add nono inside the container for path-level control:

# Before: Docker without filesystem restrictions inside the container
docker run -v $(pwd):/work my-agent

# After: nono inside the container restricts access to /work only
docker run -v $(pwd):/work my-nono-agent -- my-agent

Decision Flowchart

Do you need a different OS or runtime?
├── Yes → Container (add nono inside for filesystem control)
└── No
    │
    Do you need resource limits (CPU/memory)?
    ├── Yes → Container + nono
    └── No
        │
        Do you need process isolation?
        ├── Yes → Container + nono
        └── No
            │
            Is startup time or zero setup important?
            ├── Yes → nono
            └── No → Both work; consider combining for defense in depth

Summary

Use Case	Recommendation
AI coding agents (Claude, Aider, etc.)	nono (or both for extra isolation)
CI/CD pipelines	Both (container for environment, nono for filesystem control)
Interactive development	nono
Untrusted code execution	Both
Reproducible environments	Container (consider adding nono inside)
Quick sandboxing, zero setup	nono
Resource-limited execution	Container (consider adding nono inside)
Maximum security	Both

Next Steps

Security Model - Understanding nono’s guarantees
Profiles - Pre-configured sandboxes for common agents
Installation - Get started with nono

Getting Started

Policy

Sessions

Packaging

Networking

Secrets

Audit

Supply Chain Security

Rollback

Resource Limits

Architecture

Reference

Development

nono and containers

Quick Comparison

What nono Adds

Zero-Latency Startup

Direct Access to Your Working Directory

Automatic Credential Protection

Zero Configuration

What Containers Add

Full Environment Isolation

Resource Limits

Process Isolation

Reproducible Environments

Using Both Together

Threat Model Comparison

What nono Protects Against

What Containers Protect Against

What Neither Protects Against

Performance Comparison

Startup Time

Memory Overhead

Disk Usage

Adding nono to an Existing Workflow

Decision Flowchart

Summary

Next Steps

​Quick Comparison

​What nono Adds

​Zero-Latency Startup

​Direct Access to Your Working Directory

​Automatic Credential Protection

​Zero Configuration

​What Containers Add

​Full Environment Isolation

​Resource Limits

​Process Isolation

​Reproducible Environments

​Using Both Together

​Threat Model Comparison

​What nono Protects Against

​What Containers Protect Against

​What Neither Protects Against

​Performance Comparison

​Startup Time

​Memory Overhead

​Disk Usage

​Adding nono to an Existing Workflow

​Decision Flowchart

​Summary

​Next Steps

Quick Comparison

What nono Adds

Zero-Latency Startup

Direct Access to Your Working Directory

Automatic Credential Protection

Zero Configuration

What Containers Add

Full Environment Isolation

Resource Limits

Process Isolation

Reproducible Environments

Using Both Together

Threat Model Comparison

What nono Protects Against

What Containers Protect Against

What Neither Protects Against

Performance Comparison

Startup Time

Memory Overhead

Disk Usage

Adding nono to an Existing Workflow

Decision Flowchart

Summary

Next Steps