Gemini CLI: A Complete Guide to Google's Open-Source Terminal AI Agent

TL;DR Gemini CLI is Google's open-source terminal AI agent (Apache 2.0). ⚠️ Announced end-of-service on 2026/06/18 — official migration path is Antigravity CLI. Free accounts get 60 requests/minute and 1,000 requests/day; Skills, Hooks, and Subagents all carry over.

#gemini #google #ai-tools #cli #coding-agent #open-source #antigravity

Table of Contents

Installation
Free Tier
Core Features
Gemini 3 Pro Integration
Relationship with Gemini Code Assist
More Than Just Coding
Typical Use Cases
Positioning vs. Other Tools
References
Migrating to Antigravity CLI
Further Reading
Changelog

🌏 中文版

⚠️ Deprecation Notice (2026/05/19) Google has announced that Gemini CLI will stop serving all free, Pro, and Ultra users on June 18, 2026. The official successor is Antigravity CLI. Enterprise users (Gemini Code Assist Standard/Enterprise or Google Cloud API key) are not affected by this deadline. See the official migration announcement for details.

Gemini CLI is Google’s open-source AI agent that brings Gemini’s capabilities directly into your terminal. It uses a ReAct (Reason and Act) loop, combining built-in tools and MCP servers to tackle complex tasks.

Installation

# Run without installing
npx @google/gemini-cli

# Install globally
npm install -g @google/gemini-cli

Open-source license: Apache 2.0.

Free Tier

This is one of Gemini CLI’s most compelling selling points:

Item	Quota
Requests per minute	60
Requests per day	1,000
Requires	Personal Google account

No credit card required, no API key needed (for the free tier) — just sign in with your Google account.

Core Features

Feature	Description
Google Search grounding	Built-in search capability for real-time, up-to-date answers
File operations	Read, write, and edit local files
Shell commands	Execute arbitrary commands in the terminal
Web fetching	Retrieve web page content
MCP support	Connect custom tools via the Model Context Protocol
1M token context	Native support for an extremely long context window

Gemini 3 Pro Integration

Gemini CLI integrates Gemini 3 Pro — Google’s most powerful reasoning model:

Better instruction following: Enhanced reasoning leads to more accurate task interpretation
Agentic coding: Autonomous coding for complex engineering tasks
Advanced tool use: Smarter workflow composition

Gemini 3 Pro is available in Gemini CLI for Google AI Ultra subscribers, or via a paid API key.

Relationship with Gemini Code Assist

	Gemini CLI	Gemini Code Assist
Interface	Terminal	VS Code extension
Underlying engine	Standalone CLI	Powered by Gemini CLI
Plans	Free / API key	Free / Standard / Enterprise

Gemini Code Assist’s agent mode in VS Code is essentially a subset of Gemini CLI’s functionality. Both share the same core capabilities.

More Than Just Coding

Gemini CLI is not limited to writing code:

Content generation: Produce documentation, translations, and summaries
Problem solving: Analyze logs, debug issues, process data
Deep research: Conduct real-time research using Google Search grounding
Task management: Organize workflows and automate routine tasks

Typical Use Cases

Fix bugs + run tests: Describe the problem; Gemini locates, fixes, and verifies with tests
New feature development: Provide a spec; get incremental code generation
Code comprehension: Use the 1M token context to load an entire project and ask questions
Cross-language translation: Rewrite a Python snippet in TypeScript

Positioning vs. Other Tools

Gemini CLI’s core strengths: a generous free tier, a 1M-token context window, real-time Google Search grounding, and a fully open-source codebase (Apache 2.0). It’s a great fit for developers on a budget who want to try an AI coding agent, or for scenarios involving very large codebases.

References

Migrating to Antigravity CLI

At Google I/O 2026 (2026/05/19), Google announced that Gemini CLI’s functionality will be fully taken over by Antigravity CLI. Antigravity CLI is the terminal interface for the Google Antigravity 2.0 platform — rewritten in Go for faster execution and with support for asynchronous agent workflows.

Retained Features

The following features carry over completely:

Feature	Notes
Agent Skills	Automatically available after migration; `/skills` command works the same way
Hooks	Identical behavior — no reconfiguration needed
Subagents	Parallel agent capabilities are preserved with improved performance
Extensions → Plugins	Extensions are renamed to Antigravity plugins and can be migrated automatically
MCP Servers	Same `/mcp` command is supported; config file path has changed

Quick Migration

# Install Antigravity CLI
# macOS / Linux
curl -fsSL https://antigravity.google/install.sh | sh

# Migrate existing Extensions → Antigravity plugins
agy plugin import gemini

MCP config difference: Gemini CLI’s mcpServers lives in settings.json. Antigravity CLI moves this to a dedicated mcp_config.json (global path: ~/.gemini/antigravity-cli/mcp_config.json; workspace: .agents/mcp_config.json). The remote MCP server field name changes from url to serverUrl.

Key Dates

2026/06/18: Gemini CLI stops serving personal free, Pro, and Ultra users
Enterprise users (Gemini Code Assist Standard/Enterprise or Google Cloud API key): not yet affected; separate notice to follow

Full migration guide: antigravity.google/docs/gcli-migration

Changelog

2026-05-21: Added Gemini CLI deprecation notice (2026/06/18) and Antigravity CLI migration guide; updated tldr, tags, and references