MARS CLI

A fast, terminal-native AI coding agent — powered exclusively by MarsAI.

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MARS CLI (mars) is a coding agent that lives in your terminal. It reads, writes, and runs code in your project, plans multi-step work with subagents, and answers quick questions on a free model without touching your session context. One provider, one login: MarsAI.

Screenshots

Startup header

Free-model ? ask

mars --help

Features

• MarsAI-only provider — sign in with OAuth device flow (/mars) or MARSAI_API_KEY. No provider zoo to configure.
• Free-tier delegation — inline ?question, /ghost (replay last prompt), /budget, subagents, and auto-recon all run on marsai/auto-free at zero cost, isolated from your main session context.
• Subagents — single, parallel, and chained dispatch to isolated child mars processes, each with its own context window. Explore-first auto-recon appends a repo map to the system prompt on the first turn of a fresh session.
• Web tools — web_fetch (manual-redirect fetching with per-hop private-network blocking) and web_search (DuckDuckGo lite).
• /handoff - export a session as JSONL with copy-paste import instructions; move work between machines or teammates.
• /init - generate or improve AGENTS.md: collects project stats (manifests, scripts, workspaces, file counts), then the agent investigates the repo and writes the instruction file itself.
• mars pack - export tracked files as XML context for handoff to another model. Gitignore-aware, skips binaries, redacts secrets, caps output at 200KB.
• /update - self-update from the npm registry, async and non-blocking.
• Sessions, themes, MCP, codemode — resumable sessions, themable TUI, MCP server support, and JavaScript code mode.
• Safe by default — trust dialogs for project folders, SSRF-protected redirects, SIGTERM→SIGKILL child process escalation.

Install

npm install -g @mars_ai/marscli

Requires Node.js >= 22.19.

Quickstart

cd your-project
mars

First run: sign in via /mars (OAuth device flow) or export MARSAI_API_KEY. Then just type what you want built.

Handy keys:

Input	Effect
?question	Ask a free model without touching session context
/ghost	Replay the last prompt on the free model
/init [focus]	Create or improve AGENTS.md (focus text optional)
!cmd	Run a shell command inline
ctrl+o	Expand the transcript
/handoff	Export the session as JSONL

Non-interactive:

mars -p "refactor server.js to use ES modules"   # one-shot prompt
mars --mode json -p "list dead exports"           # JSON output
mars pack                                         # repo as XML for another model
mars pack --query "src/**/*.ts" --max-bytes 100000
mars pack --full                                  # no size cap

Configuration

Env var	Purpose
MARSAI_API_KEY	MarsAI API key (alternative to OAuth login)
MARSAI_SUBAGENT_MODEL	Pin the model used for free-tier delegation
MARS_NO_RECON	Set 1 to disable auto-recon in spawned children

Settings live in .mars/ (project) and ~/.mars/ (global).

Documentation

• Extensions guide
• Examples
• mars --help

License

MIT — forked from mars by Mario Zechner. Rebranded and maintained as MARS CLI with the MarsAI provider.