Start here

Install

Install the Submilli CLI and server, and the skill for your coding assistant, and check that each works.

Set up with your coding agent

Open your coding agent with the Submilli setup prompt and skill instructions, or copy the prompt into your agent.

View setup prompt

Help me set up Submilli in my project. Read and follow the Submilli skill at https://github.com/submilli/submilli-runtime/blob/main/skills/submilli/SKILL.md, the official setup instructions at https://github.com/submilli/submilli-runtime/blob/main/skills/submilli/references/setup.md and the quickstart at https://submilli.ai/docs/quickstart/ first. Confirm the project directory, check whether submilli and submilli-server are already installed, and use the documented installer for my OS only if needed. Preserve existing pinned versions and local edits. Install the skill for this assistant in the project: use submilli skill install --agent claude --project . for Claude Code, or submilli skill install --agent codex --project . for Codex. Read the installed skill and use it to guide setup. Verify the installation and run a small local example without paid model calls or external side effects. Tell me if I need to restart the assistant to discover the skill, and report what you actually verified.

Use the skill setup box above to get started with Codex or Claude Code. The prompt asks your agent to install and read the Submilli skill in this project, then verify the CLI and server. If you prefer to install them yourself, follow the manual steps below.

Two things to install: the submilli command, which comes with the submilli-server binary, and the Submilli skill for your coding assistant. The quickstart needs the first. The tutorials later in the book use the second.

Submilli is open source under the Apache License 2.0. The source, the curated Packages, and the releases are in the submilli/submilli-runtime repository.

Install the CLI and server yourself

macOS and Linux:

Command

curl -fsSL https://submilli.ai/install.sh | sh

Windows (PowerShell):

irm https://submilli.ai/install.ps1 | iex

One line, and you have both binaries. Check the CLI:

Command

submilli --version

submilli 0.3.0

Command

submilli builtins Map

/**
 * A hash-backed key-value collection. Keys are compared by structural equality through each key's `equals` method; lookup buckets via `hash`. Insertion-order iteration is not guaranteed in v1.
 */
interface Map<K, V> {
  /**
   * The number of entries currently in the map.
   */
  readonly size: number;
…

That is the declaration of one of the language’s built-ins, printed by the same compiler that will run your programs. Now the server. It checks a token on every request, so it needs one to start:

Command

export SUBMILLI_SERVER_TOKEN=$(openssl rand -hex 32)
submilli-server &

ts=2026-10-03T17:05:23.415Z level=info stream=log target=submilli_server::auth msg="inbound authentication enabled" tokens="SUBMILLI_SERVER_TOKEN (admin)"
ts=2026-10-03T17:05:23.423Z level=info stream=log target=submilli_server::serve msg="submilli-server listening" addr=127.0.0.1:8128 protocol=http

The submilli server commands read the same variable, so from the same shell:

Command

submilli server status
submilli server stop

status:          running
bind:            127.0.0.1:8128
pid:             16882
active sessions: 0
blueprints:      (none)

Later, submilli upgrade moves both binaries to the latest release in place.

The skill

The skill teaches your coding assistant to write Blueprints and Packages, test them, and connect your agent harness. Choose your assistant:

Assistant	Command	Installed at
Claude Code	`submilli skill install --agent claude`	`~/.claude/skills/submilli`
Codex	`submilli skill install --agent codex`	`~/.agents/skills/submilli`
Cursor	`submilli skill install --agent cursor`	`~/.cursor/skills/submilli`

Add --project . to install into the current project instead of your home directory, and commit the installed folder to share it with your team. Restart your assistant afterwards, then invoke the skill: /submilli in Claude Code, $submilli in Codex, or ask “Help me adopt Submilli in this project.”

Check an installation:

Command

submilli skill status --agent claude

It reports whether the skill is current and whether its files have been edited, and exits 0 when everything is current. The skill keeps itself current from then on.

Next: the quickstart.