Roundhouse

Roundhouse ships as one binary, roundhouse, with the analyzer, the LSP server, the MCP server and every transpile target inside it. There are two ways to get it. The snapshot binaries cover most needs; a source build is always available for everything else.

The snapshot binaries

Releases are dated snapshots, in the style of Spinel's: a tag names the day a release was cut, and what it promises is in RELEASES.md and the CI that ran on that commit. There is no semantic version to interpret — a newer date is a newer snapshot, and each one carries prebuilt binaries for:

These two are the platforms the project itself runs on daily; every CI lane that exercises the binary runs on one or the other. The release matrix also builds macOS on Intel and Windows x86-64 archives, and they are attached to each snapshot, but nothing in CI exercises them beyond roundhouse --version — treat them as a courtesy, and report what breaks.

The installer script picks the right archive and puts roundhouse in ~/.local/bin:

curl --proto '=https' --tlsv1.2 -LsSf \
  https://github.com/rubys/roundhouse/releases/latest/download/roundhouse-installer.sh | sh

Or download the archive from the releases page, unpack it, and put the one file somewhere on your PATH. There is nothing else in the archive that the binary needs.

Then:

roundhouse --version

prints the snapshot and the commit it was built from — for example roundhouse 2026.9.16 (f6aa410a). That line is the first thing to include in a bug report; it is also what the MCP server reports as its serverInfo and what the LSP reports at initialize, so an editor's log names the same build.

The binary is self-contained: no Ruby, no gems, no database, nothing to download at first run. It reads Rails source and writes files. The things it produces have their own prerequisites — a transpiled Rust project needs cargo, a Spinel binary needs the Spinel compiler — and each door's page lists them.

Building from source

The binaries cover the common case. Build from source when they don't: another platform or CPU, a commit newer than the last snapshot, a fix you are testing before it lands, or the developer tools (roundhouse-ast, dump_ir, emit_preview) that the snapshot deliberately leaves out.

You need a Rust toolchain (1.85 or later) and a working libclang: the ruby-prism-sys and ruby-rbs-sys build scripts generate their C bindings with bindgen, which loads clang's own resource headers.

• macOS: Xcode Command Line Tools (xcode-select --install) is all that's needed.
• Debian / Ubuntu: sudo apt install clang libclang-dev — both packages. Installing only libclang-dev fails with fatal error: 'stddef.h' file not found, because clang's builtin headers ship in the clang package.

Then either install straight from the repository:

cargo install --git https://github.com/rubys/roundhouse --bin roundhouse
roundhouse --version

or build in a checkout:

git clone https://github.com/rubys/roundhouse
cd roundhouse
cargo build --release --bin roundhouse
./target/release/roundhouse --version

A source build stamps --version with the checkout's commit, so a build from between snapshots is told apart from the snapshot by that commit; the same file works anywhere the snapshot binary does, including as the editor's roundhouse.serverPath.

cargo build --release without --bin also builds the cargo-only aliases (roundhouse-check, roundhouse-lsp, roundhouse-mcp) and the IR inspection tools; DEVELOPMENT.md covers those and the test suite.

What is not in the box

• Spinel. The compile door needs the Spinel compiler and its spin project tool on PATH, built from Spinel's own source snapshots. Each roundhouse snapshot names the Spinel release it was tested against in RELEASES.md; spinel.md walks through the install.
• Target toolchains. Transpiling to Go produces a Go project; running it needs Go. targets.md has the per-target list.
• The editor extension. editor.md — the VS Code client is small enough to install from the repository today.
• A Rails app to point it at. Any checkout works. If you want a known-good one, the Rails Guides store fixture (fixtures/store in the repository) checks clean, and it is the app used in the examples throughout this guide.

This page is docs/guide/install.md in the repository; edits are welcome there.