What problem does it solve? Building or testing a project often fails because the machine lacks the right language toolchains, root access, or docker. This Skill installs complete development environments (Python, Go, Rust, JVM, Android, Haskell, and more) into one disposable per-project root without sudo, without touching HOME or global caches, and without assuming anything but uv. ## Core Features & Use Cases - Tag-based provisioning: Name toolchains as tags like python@3.12, kotlin:android@35, or go:cgo; one command plans, installs, and verifies them with probes. - Hermetic isolation: Activation scripts redirect HOME, TMPDIR, XDG dirs, and every toolchain cache under the environment root, so nothing reads or writes caller state. - Cross-architecture support: Foreign-architecture binaries (e.g., x86_64 aapt2 on linux/arm64) run via qemu user-mode emulation or Rosetta 2, decided centrally. - Use Case: On a bare CI-like Linux box with only uv installed, run btm-setup-env provision python@3.12 rust to get a working, verified Python and Rust environment, then source the printed activate.sh and build. ## Quick Start Ask the agent to provision the toolchains your project needs, for example: set up a development environment with python 3.12 and go for this project using the setup-env skill.