Base Images

Sprites run on pre-configured base images that include common development tools, language runtimes, and AI coding agents. The base image is upgraded automatically without affecting your overlay filesystem.

Ubuntu DevTools (Default)

The default Sprite image is based on Ubuntu 25.04 and comes with a comprehensive development environment.

Operating System

• Base: Ubuntu 25.04
• User: sprite with passwordless sudo
• Shell: bash (default), with zsh, fish, tcsh, and ksh available

Pre-installed Languages

Language	Default Version	Version Manager	Manager Shimmed?
Node.js	22.20.0	nvm	No (requires sourcing)
Python	3.13.7	pyenv	Yes
Go	1.25.1	Direct install	N/A
Rust	1.90.0	rustup	Yes
Ruby	3.4.6	rbenv	Yes
Elixir	1.18.4	Direct install	N/A
Erlang	28.1	kerl	Yes
Java	25 (Temurin)	SDKMAN	No (requires sourcing)
Bun	latest	Direct install	N/A
Deno	latest	Direct install	N/A

AI Coding Agents

Pre-installed coding agents ready to use:

Agent	Command	Package
Claude Code	claude	@anthropic-ai/claude-code
Gemini CLI	gemini	@google/gemini-cli
OpenAI Codex	codex	@openai/codex
Cursor	cursor	cursor

System Tools

Common development tools pre-installed:

• Build tools: build-essential, clang, autoconf, automake, libtool, pkg-config
• Version control: git
• Editors: vim, nano
• Shells: bash, zsh, fish, tcsh, ksh
• Terminal: tmux, kitty
• Utilities: curl, wget, rsync, tree, htop
• Network: dnsutils, iputils-ping, net-tools, openssh-client

Language Details

Node.js

Default commands work immediately via shims: node, npm, npx, corepack.

# These work directly
node --version
npm --version
npm install express
npx create-next-app

To install or switch Node.js versions, you must source nvm first:

# Source nvm
export NVM_DIR="/.sprite/languages/node/nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"

# Now nvm commands work
nvm install 20
nvm install 18
nvm use 20
nvm alias default 20
nvm list

Python

Default commands work immediately via shims: python, pip, pipenv, poetry, virtualenv.

The pyenv command is also shimmed and works directly:

# These work directly
python --version
pip --version
pip install requests

# pyenv is shimmed - works without sourcing
pyenv install 3.12.0
pyenv install 3.11.0
pyenv global 3.12.0
pyenv local 3.11.0  # Per-directory
pyenv versions

# Virtual environments
python -m venv myenv
source myenv/bin/activate

# Or use poetry/pipenv (pre-installed)
poetry new myproject
pipenv install

Go

Default commands work immediately via shims: go, gofmt.

# These work directly
go version
go build
go run main.go
go install github.com/example/tool@latest

Go is installed directly without a version manager. Only one version is available at a time.

Rust

Default commands work immediately via shims: rustc, cargo, rustfmt, rustdoc.

The rustup command is also shimmed and works directly:

# These work directly
rustc --version
cargo --version
cargo build
cargo run

# rustup is shimmed - works without sourcing
rustup toolchain install nightly
rustup toolchain install 1.75.0
rustup default nightly
rustup default stable
rustup component add clippy
rustup toolchain list

Ruby

Default commands work immediately via shims: ruby, gem, bundle, bundler, irb, rake.

The rbenv command is also shimmed and works directly:

# These work directly
ruby --version
gem --version
gem install rails
bundle install

# rbenv is shimmed - works without sourcing
rbenv install 3.3.0
rbenv install 3.2.0
rbenv global 3.3.0
rbenv local 3.2.0  # Per-directory
rbenv versions

Elixir & Erlang

Default Elixir commands work via shims: elixir, elixirc, iex, mix.

Default Erlang commands work via shims: erl, erlc, escript, dialyzer, rebar3.

# These work directly
elixir --version
iex
mix new myapp

erl -version
rebar3 new app myapp

The kerl command is shimmed for managing Erlang versions:

# kerl is shimmed - works without sourcing
kerl list releases
kerl build 27.0 27.0
kerl install 27.0 /.sprite/languages/erlang/kerl/installs/27.0

Elixir is installed directly for the default Erlang version. To use different Elixir versions, download precompiled releases manually.

Java

Default Java commands work via shims: java, javac, jar, jshell, etc.

# These work directly
java --version
javac --version
java -jar myapp.jar

To install or switch Java versions, you must source SDKMAN first:

# Source SDKMAN
export SDKMAN_DIR="/.sprite/languages/java/sdkman"
[ -s "$SDKMAN_DIR/bin/sdkman-init.sh" ] && \. "$SDKMAN_DIR/bin/sdkman-init.sh"

# Now sdk commands work
sdk list java
sdk install java 21-tem
sdk install java 17-tem
sdk use java 21-tem
sdk default java 21-tem

Bun

Default commands work via shims: bun, bunx.

# These work directly
bun --version
bun run start
bun install
bun test
bunx create-next-app

Deno

Default command works via shim: deno.

# These work directly
deno --version
deno run script.ts
deno task start
deno compile app.ts

Filesystem Layout

Languages are installed in /.sprite/languages/ with shims in /.sprite/bin/:

/.sprite/
├── bin/                    # Command shims (in PATH)
│   ├── node
│   ├── npm
│   ├── python
│   ├── pyenv              # Shimmed - works directly
│   ├── go
│   ├── rustc
│   ├── rustup             # Shimmed - works directly
│   ├── ruby
│   ├── rbenv              # Shimmed - works directly
│   └── ...
├── languages/
│   ├── node/
│   │   └── nvm/           # Must source to use nvm
│   ├── python/
│   │   └── pyenv/         # Shimmed via /.sprite/bin/pyenv
│   ├── go/
│   │   ├── versions/      # Go versions
│   │   └── current/       # Symlink to active version
│   ├── rust/
│   │   ├── rustup/        # Shimmed via /.sprite/bin/rustup
│   │   └── cargo/
│   ├── ruby/
│   │   └── rbenv/         # Shimmed via /.sprite/bin/rbenv
│   ├── java/
│   │   └── sdkman/        # Must source to use sdk
│   ├── erlang/
│   │   └── kerl/          # Shimmed via /.sprite/bin/kerl
│   ├── elixir/
│   │   └── current/       # Symlink to active version
│   ├── bun/
│   └── deno/
├── etc/
│   └── profile.d/         # Shell initialization
└── llm.txt                 # LLM documentation

Image Updates

Base images are updated automatically without affecting your files:

• Your code and data: Stored in the overlay filesystem, preserved across updates
• System packages: Updated in the base image, applied on next boot
• Language runtimes: Base versions updated, your installed versions preserved

To check the current base image version:

cat /.sprite/version.txt

LLM Integration

Each Sprite includes documentation for LLMs at /.sprite/llm.txt. This file describes the environment and available tools, making it easy for AI assistants to understand and work with your Sprite.

Additional language-specific documentation is available in each language directory:

# General environment documentation
cat /.sprite/llm.txt

# Per-language documentation
cat /.sprite/languages/node/llm.txt
cat /.sprite/languages/python/llm.txt
cat /.sprite/languages/rust/llm.txt

Internal Tools

The base image includes several tools for interacting with the Sprite runtime from inside the environment.

curl-sprite-api

A convenience wrapper for accessing the internal API via Unix socket:

# Instead of:
curl --unix-socket /.sprite/api.sock -H "Content-Type: application/json" http://sprite/v1/services

# You can use:
curl-sprite-api /v1/services

# See all available endpoints
curl-sprite-api --help

The internal API manages:

• Services - Long-running processes that persist across reboots
• Checkpoints - Create and restore environment snapshots

See Services and Checkpoints for details.

sprite-browser

Handles browser open requests from within the Sprite. When a process tries to open a URL (e.g., xdg-open https://example.com), this tool sends an escape sequence to your terminal, which the Sprite CLI intercepts to open the URL in your local browser.

# Opens in your local browser (when connected via sprite console)
xdg-open https://example.com

sprite-console

Launches the appropriate login shell based on your local environment. When you run sprite console, this script:

1. Detects your preferred shell from the $SHELL environment variable
2. Installs terminfo if needed for proper terminal rendering
3. Starts a login shell session

Internal API Socket

The Sprite runtime exposes a Unix socket at /.sprite/api.sock for internal management. While curl-sprite-api is the recommended way to interact with it, you can also use it directly:

# Using curl directly
curl --unix-socket /.sprite/api.sock \
  -H "Content-Type: application/json" \
  http://sprite/v1/services

# Using other HTTP clients that support Unix sockets

Network Policy

Network egress policy is mounted read-only at /.sprite/policy/network.json. This file shows which domains are allowed:

cat /.sprite/policy/network.json

Network policies must be updated externally via the Sprite API—the container cannot modify its own policy. See Networking for details.