Agent skill
using-docker-in-web
Set up and use Docker in Claude Code for Web environments. Use when Docker builds fail with bridge/iptables errors, SSL certificate errors through proxy, or when working in containerized web environments.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/using-docker-in-web
SKILL.md
Docker in Claude Code for Web
Claude Code for Web runs in a restricted container environment that requires special configuration for Docker.
Detection
You're in Claude Code for Web if:
# Proxy environment is set
echo $http_proxy # Shows a proxy URL
# Running inside a container
test -f /.dockerenv && echo "In container"
# iptables is restricted
iptables -L 2>&1 | grep -q "Permission denied"
Quick Setup
# Install Docker
sudo apt-get update && sudo apt-get install -y docker.io
# Start daemon with restrictions (background)
sudo dockerd --iptables=false --bridge=none &
# Wait for daemon to be ready
sleep 3
# Verify
docker info
Building csb Images
Standard builds fail because Docker tries to create bridge networks. Use these flags:
# Build with host networking and insecure SSL (for intercepting proxy)
csb build --host-network --insecure
What these flags do:
--host-network: Uses host networking instead of bridge (which requires iptables)--insecure: Adds-kto curl commands and disables npm strict-ssl (for SSL-intercepting proxies)
Creating Sandboxes
Sandbox creation also needs host networking:
# When creating sandboxes, they'll run in the Docker network
# The proxy container won't work (needs iptables), so use --egress=all
csb create my-sandbox --egress=all
Common Errors and Fixes
"iptables: Permission denied"
The daemon is trying to manage iptables rules. Restart with:
sudo pkill dockerd
sudo dockerd --iptables=false --bridge=none &
"network bridge not found"
Same issue - daemon needs --bridge=none flag.
"SSL certificate problem"
The proxy intercepts HTTPS. Use --insecure flag with csb build, or for manual curl:
curl -k https://example.com
"npm ERR! unable to verify certificate"
npm config set strict-ssl false
npm install
npm config set strict-ssl true # Reset after
Full Workflow Example
# 1. Install and start Docker
sudo apt-get update && sudo apt-get install -y docker.io
sudo dockerd --iptables=false --bridge=none &
sleep 3
# 2. Build csb images
csb build --host-network --insecure
# 3. Create a sandbox
csb create dev --egress=all
# 4. Connect
csb ssh dev
Limitations
In Claude Code for Web:
- No bridge networking - containers share host network
- No egress proxy container (requires iptables)
- SSL verification must be disabled for builds
- GPU passthrough not available
Cleanup
# Stop all containers
docker stop $(docker ps -q) 2>/dev/null
# Stop daemon
sudo pkill dockerd
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