Editor and tooling

Beyond the compiler, NURL ships a formatter, a language server, a package manager, and a local MCP server. You can build each one separately from the repo.

Editor support

tooling/vscode-nurl/ is a VS Code extension. It also works in Cursor and Windsurf. It has syntax highlighting and a full language server. The language server gives: go-to-definition, hover, document outline, completion, workspace symbol search, folding, and nurlfmt-backed formatting on save.

git clone https://github.com/nurl-lang/nurl.git
cd nurl
./install.sh

install.sh is idempotent. It is safe to re-run. It bootstraps the compiler. It builds nurl-lsp. It symlinks it onto your PATH. It installs the VS Code extension if code / cursor / windsurf is available. Flags: --no-vscode, --no-path, --force, --uninstall.

The browser playground ships the same tokenizer. The playground ports it to Monaco. Syntax highlighting works there with no install.

Language server (nurl-lsp)

./tools/nurl-lsp/build.sh builds a stdio JSON-RPC server. It has diagnostics, go-to-definition, hover, document symbols, completion, formatting, workspace symbol search, and folding ranges. This is the engine behind the editor extension above.

Package manager (nurlpkg)

./tools/nurlpkg/build.sh builds a Cargo-shaped package manager. It handles path dependencies and registry dependencies. The registry is at reg.nurl-lang.org. Manifests work in a repo checkout and from a published tarball.

mkdir demo-app && cd demo-app
nurlpkg init demo-app                  # write nurl.toml
nurlpkg add http-router --path ../router --version 0.2.0
nurlpkg install                        # symlink deps/, write nurl.lock
nurlpkg verify                         # CI gate: exit 1 on lockfile drift

nurlpkg install nq                     # fetch + build a registry program
nurlpkg publish                        # pack + upload

Other subcommands: info, deps, remove, update, lock, login, logout, search, yank / unyank, test, bench, version, self-update.

self-update upgrades the toolchain rather than a package — normally you spell it nurl upgrade (see Install). nurlpkg update is a different thing entirely: it moves your project's dependency requirements.

MCP server (nurl-mcp)

nurlpkg install nurl-mcp gives an LLM agent a local MCP server. The server uses the installed toolchain. It can build, run, type-check, format, and compile to WebAssembly. It also gives read access to the installed standard library.

claude mcp add nurl -- nurl-mcp

Stdio is the default. The flag --http adds a token-authenticated network transport. Code execution is gated behind --allow-run. The flag --read-only strips everything but the analysis tools. This is the local counterpart to the hosted MCP endpoint. That endpoint is covered in Playground and APIs.

WebAssembly toolchain

nurlpkg install wasmbuilder     # NURL → wasm32-wasi, fully local
nurlpkg install wasmtime        # pure-NURL wasm runtime

wasmbuilder program.nu          # → program.wasm
wasmtime run program.wasm

wasmbuilder drives nurlc. It retargets the emitted IR for wasm32-wasi. It links with a bundled zig cc. wasmbuilder --doctor diagnoses a local setup.

Next

• Formatting — the rules nurlfmt enforces.
• Testing and benchmarking — nurlpkg test / nurlpkg bench in full.
• Platforms — where the toolchain runs and what it can target.
• Playground and APIs — the hosted equivalent of the MCP server.