Gemini CLI

Google brought its Gemini models to the terminal with Gemini CLI — an open-source coding agent with a 1 million token context window, Google Search integration, and MCP tool support. It’s designed for developers who work on massive codebases and want Google’s models at the command line. This guide covers what Gemini CLI does, its standout features, and where it stands today.

For more AI coding tools, explore the Developer Tools directory and our best AI tools in 2026 roundup.

What is Gemini CLI?

Gemini CLI is Google’s open-source terminal coding agent, built on the Gemini model family. Released in 2025, it joined the wave of AI coding CLIs alongside Claude Code and OpenAI Codex CLI — with Google’s own twist: an enormous context window and live Google Search access.

It can:

• Read and understand your repository — even very large ones
• Plan and execute multi-file changes
• Run commands and tests
• Search the web for current information while working
• Connect to external tools via MCP servers

As of 2026, Google has been steering its terminal coding experience toward Antigravity (its agentic development platform), so Gemini CLI’s long-term role is evolving — but it remains a capable open-source option.

How Gemini CLI works

Gemini CLI uses a ReAct loop — reasoning and acting in alternating steps:

1. You launch Gemini CLI in your project.
2. You describe a goal — “migrate this service to TypeScript.”
3. Gemini reasons — with the whole repo in context, it forms a plan.
4. Gemini acts — it edits files and runs commands.
5. Gemini searches — it can look up docs or APIs online when needed.
6. You review — changes are presented for approval.

The 1M context window means the model rarely forgets earlier parts of your codebase — a real advantage on monorepos and large services.

Key features of Gemini CLI

1M token context window

The headline feature: a million tokens of context lets Gemini CLI analyze entire large codebases at once — hundreds of files in a single session — without losing the thread.

Google Search integration

Gemini CLI can search the web live, pulling current documentation, API references, and known issues while it works — reducing the stale-knowledge problem of purely offline models.

MCP (Model Context Protocol) support

Connect Gemini CLI to external tools and data sources via MCP servers, extending it beyond code into your full toolchain.

Open source

The CLI is open source, so you can inspect and extend it, and it’s free to use with Gemini API access.

Multi-file agentic edits

Like its peers, Gemini CLI plans and executes changes across many files with reviewable diffs.

Gemini CLI vs. Claude Code vs. Codex CLI

	Gemini CLI	Claude Code	Codex CLI
Models	Gemini	Claude	OpenAI
Context window	1M tokens	200K	Large
Web search	✅ Google Search	Limited	Limited
Open source	✅ Yes	❌	✅ Yes
Best for	Huge codebases, Google stack	Deep agentic work	OpenAI stack

Gemini CLI wins on context size and live search. Claude Code excels at autonomous multi-step work with sub-agents. Codex CLI fits the OpenAI ecosystem. Pick based on the model family and codebase size you work with.

Who is Gemini CLI for?

• Google ecosystem developers using Gemini and Google Cloud.
• Engineers on very large codebases who benefit from 1M context.
• Teams using MCP-connected toolchains.
• Open-source enthusiasts who want Google models in the terminal.

It’s not for casual users (it’s a developer tool), or for teams needing a stable long-term platform while Google transitions to Antigravity. For those, Claude Code or Aider offer more established roadmaps.

How to get started with Gemini CLI

1. Install Gemini CLI — via npm or the Google developer docs.
2. Authenticate — set up your Gemini API key or Google account.
3. Open it in a repo — cd your-project && gemini.
4. Try a large-context task — ask about a whole module or monorepo area.
5. Enable search — ask a question that benefits from live web data.
6. Watch the roadmap — check Google’s Antigravity plans for the future.

Start with a codebase-wide question to feel the 1M context advantage, then move to edits and command execution.

The bottom line

Gemini CLI is Google’s take on terminal AI coding — open source, search-connected, and uniquely powerful on large codebases thanks to its million-token context. With Google’s focus shifting to Antigravity, it’s a capable tool today and a preview of where Google’s agentic direction is heading.

For a full AI coding toolkit, pair it with Claude Code and Aider, and explore the Developer Tools directory.

Official resource: Gemini CLI documentation.