jules-env

Configure ephemeral development environments in one command.

jules-env use dart

That's it. The runtime is installed, environment variables are set, and your shell is configured:

✔ brew install dart-sdk
Wrote ~/.jules/shellenv
  export PATH="/opt/homebrew/opt/dart-sdk/bin:$PATH"
  export DART_SDK="/opt/homebrew/opt/dart-sdk/libexec"

Runtime configuration

jules-env follows a recipe → plan → execute model:

1. Recipe — A recipe describes how to install a runtime. It probes the system (e.g., brew --prefix dart-sdk) but never modifies it.
2. Plan — The recipe produces an execution plan: shell commands to run, environment variables to set, and paths to prepend.
3. Execute — The plan runs. Install steps that are already satisfied (checked via an optional checkCmd) are skipped. State is persisted to ~/.jules/shellenv.

Data recipes

Recipes can also be defined as JSON files. A data recipe is a static execution plan — no system probing, no dynamic resolution. This makes them easy to generate programmatically (e.g., by an LLM). Data recipes are validated against a Zod schema at load time. See src/recipes/ollama.json for an example.

Shell environment

After execution, ~/.jules/shellenv contains the environment your runtime needs:

export PATH="/opt/homebrew/opt/dart-sdk/bin:$PATH"
export DART_SDK="/opt/homebrew/opt/dart-sdk/libexec"

Source it to activate:

source ~/.jules/shellenv

The file is appended to on subsequent runs, so multiple runtimes compose cleanly.

CLI reference

jules-env use <runtime> [options]

Arguments

• <runtime> — The runtime environment to setup (e.g., dart).

Options

| Flag | Description | Default | |------|-------------|---------| | --version <v> | Version of the runtime to install | latest | | --dry-run | Simulate execution — no changes are made | false | | --preset <p> | Apply a configuration preset (if available for the runtime) | — | | -h, --help | Display help | — |

Dry run

Preview what would happen without touching the system:

jules-env use dart --dry-run

Available recipes

| Runtime | Recipe | Type | Description | |---------|--------|------|-------------| | Dart | dart | Code | Installs the Dart SDK (Homebrew on macOS, apt on Linux) | | Ollama | ollama | Data | Installs Ollama with EmbeddingGemma model |

Installation

npm

npm install jules-env

From source

git clone <repository_url>
cd jules-env
bun install
bun run build

Development

Prerequisites

• Bun
• Homebrew (macOS only, used by Dart recipe)

Run tests

bun test

Build

bun run build          # Build both Node.js bundle and Bun binary
bun run build:node     # Node.js bundle only (dist/cli.mjs)
bun run build:binary   # Standalone Bun binary only (jules-env)

Type check

bun run typecheck

Prepublish checks

Run the full validation suite before publishing:

bun run check:all

This validates version, runs type checks, tests, builds both targets, and smoke-tests the outputs.