Install

Karajan v4 attaches to the AI agent you already work with (Claude Code, Codex, Gemini CLI, Cursor). You install it once per machine, activate it once per project, and from then on your agent follows the method and git enforces it.

One installer, complete result: curl -fsSL https://karajancode.com/install.sh | sh installs the full product — it uses your Node (≥ 22.12) if present, and auto-provisions the official Node LTS into ~/.karajan/node (checksum-verified, nothing system-wide) if not. npm install -g karajan-code works too if you prefer it explicit. A CLI-only single binary exists behind --standalone for machines where you deliberately want no Node. Requires git, and at least one AI agent CLI — two enables cross-AI review; three enables arbitration.

The one-liner (recommended)

In your project directory, tell your agent just this — it routes itself:

I want to use Karajan in this project: read https://karajancode.com/start.md
and do what it says.

The router prompt makes your agent check whether kj is installed (and set up the whole machine if not), detect whether this is a new project or an existing codebase, activate the environment accordingly, and stop and WAIT for you whenever a step needs your permission (sudo/administrator), an account, or kj exits with code 3 (PENDING USER ACTION) — a partial install is a failed install. The prompts are versioned with kj itself (docs/prompts/).

Prefer to drive each phase yourself? The three flows below are the same thing, split out.

1. Set up your machine (once)

With your AI CLI

Read https://karajancode.com/install-machine.md and do what it says: install
Karajan Code on this machine, FULLY operational. Ask me before each install;
if a step needs elevated privileges (sudo/administrator) or kj exits
with code 3, STOP, show me the exact commands and WAIT for my go-ahead.

Manual

curl -fsSL https://karajancode.com/install.sh | sh   # full product; --standalone for CLI-only
kj doctor                                            # explains anything missing
kj install-tools                                     # completes the stack; exit 3 = pending user action

Full product always: uses your Node ≥ 22.12 or auto-provisions the official LTS (checksum-verified, in ~/.karajan/node). Equivalent: npm install -g karajan-code.

2. Start a new project

With your AI CLI

This machine already has kj. Read https://karajancode.com/project-new.md and
activate Karajan in THIS project (new). Stop and wait for me if anything
needs my permission, an account, or kj exits with code 3.

Manual

kj init                    # config, rules, quality tooling (agent-safe without a TTY)
kj env install             # method into CLAUDE.md/AGENTS.md/GEMINI.md + RAG index (exit 3 if it cannot index)
kj harden                  # git hooks: lint, commit policy, the review gate runner
kj review --install-gate   # commits now REQUIRE a cross-AI verdict
git config core.hooksPath .karajan/hooks

Commit the generated contract files (.karajan/review-gate, .karajan/hooks/, .karajan/adrs/, the agent rule files) — everyone who clones inherits the environment (each clone repeats the core.hooksPath config once).

3. Adopt Karajan in an existing project

With your AI CLI

This machine already has kj. Read https://karajancode.com/project-legacy.md
and adopt Karajan in THIS existing codebase: work on a branch, respect the
project's own configs, run kj onboard first, and stop and wait for me if
anything needs my permission or kj exits with code 3.

Manual

git switch -c chore/adopt-karajan   # never on the default branch
kj onboard                          # brownfield analysis → Architecture Brief
kj init && kj env install && kj harden && kj review --install-gate
git config core.hooksPath .karajan/hooks

kj seeds configs only when NO variant exists — your eslint.config.mjs, .prettierrc or biome.json stay untouched (covered). The RAG index over your existing code is the main prize: your agent queries it instead of guessing. Land the contract files through your repo’s normal flow (branch + PR).

Uninstalling / opting out

Every gate is a file you can see: remove .karajan/review-gate to disable the review gate, unset core.hooksPath to disable the hooks, delete the managed block in the rule files to remove the method. Nothing is hidden.