Gemini CLI

Gemini CLI is Google's open-source (Apache-2.0) AI agent that runs in your terminal. You install it with npm, npx, or Homebrew, point it at a project, and describe what you want in plain language. It reads and writes files, runs shell commands, fetches URLs, and grounds answers with Google Search — driven by Gemini models (the current line leads with Gemini 3) with a 1M-token context window. The same agent core also powers the Gemini Code Assist IDE extensions.

It is aimed at developers who live in the terminal and want a capable agent without leaving the shell or paying for API usage up front. Signing in with a personal Google account once unlocked a generous free allowance — but as of June 18, 2026 that free, Pro, and Ultra access has moved to Antigravity CLI (see the warning below); paid API keys and enterprise licenses remain the way to keep using Gemini CLI directly.

Highlights

• 1M-token context — Gemini's large context window lets the agent reason over big codebases and long docs in a single session.
• Built-in tools — file system operations, shell execution, web fetch, and Google Search grounding ship in the box; no plugins required for the basics.
• MCP support — connect Model Context Protocol servers to extend the agent with databases, APIs, and custom tooling.
• GEMINI.md context files — drop project-level instructions in GEMINI.md so the agent follows your conventions automatically.
• Multimodal input — feed it PDFs, images, and sketches, not just text.
• Checkpointing — enable it in settings.json and the agent snapshots your project before file modifications; use /restore to roll back any step via a shadow Git repo, without touching your real Git history.

In an AI-assisted workflow

Gemini CLI fits the terminal-native loop: open a repo, start the agent, and let it plan and apply changes while you review. A typical first run looks like this:

npm install -g @google/gemini-cli
cd your-project
gemini
# then, at the prompt:
# > Add input validation to the signup handler and update the tests

It edits files on disk and runs your test or lint commands, so you review the diff rather than copy-paste from a chat window.

Good to know

Gemini CLI is open source under Apache-2.0 and runs on macOS, Windows, and Linux (Node.js 20+). Install via npm/npx, Homebrew, MacPorts, or Anaconda. A personal Google account once offered a free tier of 60 requests/minute and 1,000 requests/day on Gemini models; that free/Pro/Ultra access ended June 18, 2026 (see below). You can still bring a Gemini API key or use a Gemini Code Assist Standard/Enterprise license.