Back in November I looked at a problem and thought "that's going to be fun to solve." GitHub Copilot CLI running inside a Docker sandbox needs Docker access. Testcontainers, integration tests, build pipelines. They all need a working Docker socket. The obvious answer? Mount /var/run/docker.sock into the container. The obvious answer is also terrifying. That socket is root access to your host machine. Any image, privileged containers, host filesystem mounts. For a human dev, you trust yourself. For Copilot running autonomously... not so much. Last year I built an Airlock feature that hardens network traffic, routing everything through an allowlist-enforcing proxy. That was step one. The Docker socket broker was the piece I kept putting off because the problem was harder. The broker sits between the container and the real Docker daemon. Every API call goes through it. 65 endpoints explicitly allowed, everything else blocked. When Copilot tries to create a container, the broker inspects the body: checks the image against an allowlist (empty by default, you name what you trust), blocks privileged mode, blocks host namespace sharing, blocks mounts to /etc, /root, /var, and the socket itself. Combine it with the Airlock I built last year and sibling containers spawned by Copilot get auto-joined to the isolated network too. Network-level and API-level lockdown at the same time. It wasn't one of those "throw a single prompt at it and it's solved" problems. In standard mode, everything works: Testcontainers, docker builds, multi-service setups. Through Airlock, some scenarios like Testcontainers port connectivity still need work. The feature I built first is ironically the part holding up the last 10%. copilot_here is growing in ways I didn't expect for a tool I built because I was too paranoid to give GitHub Copilot full shell access. 6 external contributors. 81 stars on GitHub. 24.9k container image downloads in the last 30 days (according to GitHub Packages stats). If you're running GitHub Copilot CLI and want Docker access without the "hope nothing goes wrong" approach, the deep dive on how the broker works is linked in the comments. And if you find it useful, a star on GitHub helps more than you'd think. #Docker #DevOps #OpenSource #GitHubCopilot #Security
Eddie K.
2w
curious to hear what you think of https://docs.docker.com/ai/sandboxes/
Deep dive on how the broker works: https://gordonbeeming.com/blog/2026-04-09/how-copilot-here-brokers-docker-in-docker-safely GitHub repo (star it while you're there): https://github.com/GordonBeeming/copilot_here