Developer Splits AI Docker Sandbox Into Three Repos After Using It to Ship iOS App

A developer has publicly released a three-way split of their AI coding sandbox project, originally published in February as a single repository called ai-sandbox-dkmcp. The original repo combined a devcontainer template, a host-side MCP server, and an in-container tool discovery server into one codebase. Before making the split public, the developer privately restructured it into three separate repos — AI Sandbox, HostMCP, and SandboxMCP — and used that setup to build and ship a real iOS app called とけるよ. Building the app inside the sandbox exposed practical limitations, including the need for per-tool timeout declarations and Xcode-specific host tools, which led to meaningful improvements beyond what demo usage alone would have surfaced. Since going public, the individual repos have continued to receive updates, including a formal installer for HostMCP, host-path masking to prevent username leakage, and nested-git-repo detection in SandboxMCP.