Editor Setup

Every editor integration talks to the same server: rnx lsp over stdio. It typechecks the open files on every change and pushes back errors and lint warnings with their E/L codes. The fastest way to get it running is the setup command:

rnx setup vscode   # or: zed, helix, neovim

rnx itself must be on PATH first — that is the one thing every editor needs. If it is not installed yet:

curl -fsSL https://rnx.dev/install.sh | sh
rnx --version

Each rnx setup <editor> prints exactly what it changed and what to do next. Unknown names fail with the supported list, so rnx setup emacs tells you the four it knows. The rest of this page shows what the command does per editor, so you can also do it by hand.

Check that the server answers before blaming the editor:

fn Main(): Int {
    let total = [10, 20, 30].reduce(0, (acc, n) => acc + n);
    assert(total == 60, "sum");
    return total - 60;
}

rnx check main.rnx

Exit code 0 with no output means the file is clean — the same result the editor should show as zero squiggles.

VS Code

rnx setup vscode

The command installs the packaged extension when it finds a local .vsix next to the checkout and the code CLI on PATH. Otherwise it prints manual steps, because the extension is not on the Marketplace — install it from source:

cd editors/vscode
npx vsce package
code --install-extension rasmalai-*.vsix

The extension activates on *.rnx files and starts rnx lsp with rnx from PATH. If your binary lives elsewhere, point it at the right one in settings:

{
  "rasmalai.serverPath": "/home/you/.rnx/bin/rnx"
}

Reload the window after installing, then open a .rnx file. Hover, go-to-definition, and diagnostics all come from the running server.

Zed

rnx setup zed

Zed has no registry package for Rasmalai, so setup is a dev extension. The command prints these steps with the exact checkout path:

1. Open Zed, then Extensions → Install Dev Extension, and select editors/zed in your Rasmalai checkout.
2. Add the language server to ~/.config/zed/settings.json:

{
  "lsp": { "rnx-lsp": { "binary": { "path": "rnx", "args": ["lsp"] } } },
  "languages": { "Rasmalai": { "language_servers": ["rnx-lsp"] } }
}

3. Confirm rnx is on PATH, restart Zed, and open a .rnx file.

Helix

rnx setup helix

The command appends editors/helix/languages.toml to ~/.config/helix/languages.toml (or $XDG_CONFIG_HOME/helix/languages.toml), backing up your existing file to languages.toml.bak first. Running it twice is safe — it detects the stanza and stops. By hand, merge this into yours:

[[language]]
name = "rasmalai"
scope = "source.rnx"
file-types = ["rnx", "Project.config", "Project.deplock"]
roots = ["Project.config", ".git"]
comment-tokens = ["//"]
block-comment-tokens = [{ start = "/*", end = "*/" }]
indent = { tab-width = 4, unit = "    " }
language-servers = ["rnx-lsp"]

[language-server.rnx-lsp]
command = "rnx"
args = ["lsp"]

# Rasmalai manifests are `.rnx` modules; highlight them as such.

Restart Helix and open a .rnx file; the server starts on its own. Project.config files get Rasmalai highlighting too, since they are .rnx modules.

Neovim

rnx setup neovim

The command copies editors/neovim/rasmalai.lua to ~/.config/nvim/lua/rasmalai.lua (existing files are backed up to rasmalai.lua.bak), then asks you to source it from your init.lua:

require("rasmalai")

The plugin itself sets the rasmalai filetype and starts the server per buffer:

vim.filetype.add({
    extension = {
        rnx = "rasmalai",
    },
    filename = {
        ["Project.config"] = "rasmalai",
        ["Project.deplock"] = "rasmalai",
    },
})

vim.api.nvim_create_autocmd("FileType", {
    pattern = "rasmalai",
    callback = function()
        vim.lsp.start({
            name = "rasmalai",
            cmd = { "rnx", "lsp" },
            root_dir = vim.fs.root(0, { "Project.config", ".git" }),
        })
    end,
})

Restart Neovim and open a .rnx file. The server roots itself at Project.config (or .git) so diagnostics resolve imports across the project.

When it does not work

• rnx: command not found in the editor log means PATH differs between your shell and the editor. Launch the editor from the shell once, or set an absolute binary path (VS Code's rasmalai.serverPath, Zed's binary.path).
• Stale squiggles after an upgrade mean the editor kept an old server alive. Restart the editor so it respawns rnx lsp from the new binary.
• To see the raw protocol, most clients have a trace setting — VS Code exposes it as rasmalai.trace.server. Server-side log lines go to stderr, never to the protocol stream.

From here, the AI Assistants page wires the same toolchain into agents through rnx mcp.