The product

The cars binary is written in Rust with ratatui and tokio. With no goal it opens the Welcome screen, where Tab and the arrow keys set the model, parallelism, story timeout, context and planner.

The engine builds the Context (a CLAUDE.md summary of the target directory, skipped with --skip-context), asks the Planner for a Plan and shows it on the Review screen. Press r to refine the plan with feedback, accept it, or quit.

Each run starts the bundled TypeScript orchestrator as a subprocess. It is a Mozaik agentic environment: the Conductor, StoryFactory, story agents and Operator are the core participants, and every coordination step is a typed item on the shared bus.

The Conductor walks the DAG level by level, asks the StoryFactory to spawn a story agent per story and applies replans only at level boundaries.

The Critic, Surgeon, Librarian, Sentry, Auditor and Finalizer watch bus traffic and may emit items back. The Critic, Librarian, Sentry and Surgeon are on by default and each has a --no-… flag.

The Cartographer turns bus items into frames for the TUI, one JSON line each.

next-playwright, next-appium, next-react-query and mcp-scaffold write a fixed PRD from an instruction with no Planner call, then run it through resume.

A run executes one PRD (prd.json in the target directory) on one run branch and writes one audit log, by default ~/.cars/runs/<run-id>.jsonl.

A session lock (cars.lock) stops two cars instances running in the same directory.